new-technology-could-generate-electricity-from-wastewater-and-seawater

Researchers at Stanford University have developed a “mixing entropy battery” (MEB) that can harness energy from the mixing of fresh and salt water. The energy created this way is sometimes called “blue energy.” According to a Stanford news release, the team’s objective is to apply the technology to coastal wastewater treatment plants and to use the electricity generated to make the plants energy-independent and carbon-neutral.

“Blue energy is an immense and untapped source of renewable energy,” said Kristian Dubrawski, a postdoctoral scholar in civil and environmental engineering at Stanford. “Our battery is a major step toward practically capturing that energy without membranes, moving parts or energy input.”

Development of a mixing entropy battery (MEB) depends upon the motion of sodium and chlorine ions from seawater into and out of inexpensive electrode materials. (Image source: Stanford)

Electrochemistry

The Stanford battery isn’t the only technology available to capture blue energy, but it’s the first to use battery electrochemistry instead of pressure or membranes. The present work is based on earlier research at Stanford that tapped into salt gradients to produce electricity, but that effort required an expensive electrode made from silver, and an initial energy input to begin the process.

The new Stanford battery floods a tank with salt-free water (which can be wastewater effluent. The tank contains electrodes which release sodium ions (Na ) and chlorine ions (Cl–) from the electrodes into the solution. This motion of ions also causes a current to flow from the anionic electrode to the cationic electrode. Then, a rapid exchange of the wastewater effluent with seawater allows the electrodes to reincorporate the sodium and chloride ions, reversing the electric current flow. Energy is recovered during both the freshwater and seawater flushes. This means that the battery is constantly discharging and recharging without needing any input of energy. As reported in a paper in the journal ACS Publications, energy is recovered during both the freshwater flush (43.6% of the total energy recovered) and the seawater flush (56.4% of the total energy recovered), with no upfront energy investment.

Unlike the earlier effort, that used expensive materials as the electrodes, this new MEB is cost-effective. The electrodes in the new MEB are made with Prussian Blue, a material widely used as a pigment and medicine, that costs less than $1 a kilogram, and polypyrrole, a material used experimentally in batteries and other devices, which sells for less than $3 a kilogram in bulk. The materials are relatively robust and a polyvinyl alcohol and sulfosuccinic acid coating protects the electrodes from corrosion when in contact with seawater.

Wastewater a Good Starting Point

Wastewater treatment is a good starting point for a practical application of the Stanford MEB study. The water treatment process is energy-intensive, accounting for about three percent of the total US electrical load. If sufficient blue energy could be generated by an MEB system, a wastewater treatment plant could be self-sufficient and operate off the grid.

According to the Stanford news release, “The researchers tested a prototype of the battery, monitoring its energy production while flushing it with alternating hourly exchanges of wastewater effluent from the Palo Alto Regional Water Quality Control Plant and seawater collected nearby from Half Moon Bay. Over 180 cycles, battery materials maintained 97 percent effectiveness in capturing the salinity gradient energy.” The team also reported that every cubic meter of freshwater that mixes with seawater produces about .65 kilowatt-hours of energy – enough to power the average American house for about 30 minutes. If the 68% efficiency achieved in a small prototype MEB can be achieved at full-scale, the energy produced would be sufficient to meet much or even all of the electrical energy demands for a conventional wastewater treatment plant.

“It is a scientifically elegant solution to a complex problem,” Dubrawski said. “It needs to be tested at scale, and it doesn’t address the challenge of tapping blue energy at the global scale – rivers running into the ocean – but it is a good starting point that could spur these advances.”

The Battery Show and Electric & Hybrid Vehicle Technology Expo 2019 conference will take place in Novi, Michigan on September 10-12, 2019. Four days, eight tracks, and over 80 sessions, curated by industry experts will bring battery and electric vehicle technologies into clear focus.

Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

Drive World with ESC Launches in Silicon Valley

This summer (August 27-29), Drive World Conference & Expo launches in Silicon Valley with North America’s largest embedded systems event, Embedded Systems Conference (ESC). The inaugural three-day showcase brings together the brightest minds across the automotive electronics and embedded systems industries who are looking to shape the technology of tomorrow.

Will you be there to help engineer this shift? Register today!

pre-owned-electric-vehicle-models-provide-an-affordable-way-to-go-electric
  • INTRODUCTION

    Electric Vehicles (EVs) are finally reaching a stage where they can be used as practical vehicles. Increased range (some EVs can go over 250 miles on a charge) and the deployment of EV charging stations nationwide is helping to inch electrification of transportation toward the mainstream. But what of all of those vehicles that represented the early attempts at building and selling EVs? Many of them are available on the used market, often for surprisingly low prices.

    In the not too distant past, some automakers sold EVs that were designed solely to comply with the California regulations that required that car makers offer a percentage of their fleet with zero emissions. Others embraced the idea that electrification might be the future. The EVs built in that first wave, between 2011 and 2016, were typically small, expensive, and had a range of 60-100 miles on a charge.

    Buying a used car is always a risk—even with good documentation and service records, it is still hard to know how well a vehicle has been maintained and whether it has been abused. The good news about used electric vehicles is that EVs, with fewer moving parts than traditional gasoline powered vehicles, have been shown to be mechanically robust and reliable, requiring little beyond routine maintenance. In addition, because of their limited range, they often have accumulated quite low mileage for their year, another positive.

    But there is one major concern: the battery pack. The condition of the lithium ion battery pack that powers EVs depends enormously on how it has been treated during its lifetime. Repeated fast charging, completely depleting the battery, or operation at hot or cold temperature extremes can result in a battery pack with reduced capability when compared to when it was new. Just normal aging of a pack can result in a reduction of around 5% capacity per year. Many car makers placed warranties on their battery packs, typically 8 years or 100,000 miles. Some early EVs on the used market are nearing that age limit. So the range quoted for a new EV in 2015 may not be reached by a used EV in 2019 with an aging pack.

    There is some good news for those contemplating a used EV. The cost of lithium ion batteries has fallen dramatically, from well over $1000 per kilowatt-hour (kW) just a few years ago to less than $200 per kWh today. There has grown up a cottage industry of specialists who can rejuvenate a used EV pack, replacing malfunctioning cells and returning them to nearly new capacity. There are also some aftermarket computer tools available to assess to condition of a pack—suffice it to say that any buyer of a used EV should do their homework before considering such a purchase.

    To examine the prices of some available used EVs, Design News reached out to Kelly Blue Book (KBB) to provide current used car prices. KBB is an industry standard for reliable used car pricing. We chose to price our cars as if they were in Very Good condition and if we were buying from a dealer. The prices when buying from a private seller might be slightly lower. We reported the current used price for the first year a vehicle was available, the used price for a 2018 model of the vehicle or the last year it was available, and the new vehicle price (MSRP from KBB) for the last year it was available, or for 2019 if the vehicle is still available.

    With prices that range from less than $5,000 to more than $60,000, here are some used EVs to consider.

    Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

    (Image source: BMW)

  • Nissan Leaf SL (2011-2019)

                                        KBB Price

    New     2019                $35,030           Range: 215 miles

                2018                $23,982           Range: 150 miles

                2011                $5,419             Range: 72 miles

    Battery Warranty: 8 years/100,000 miles

    Summary:

    Nissan was one of the first of the major car companies out of the gate, into production with its all-electric Leaf in 2011. Since that time the company has sold more than 300,000 Leaf’s making it the biggest selling EV in the world. The Leaf is easy to drive, reasonably comfortable, and well-made, and as long as you don’t drive more than 70-100 miles in a day, a used Leaf would make a fine commuter car. The larger 30 kWh battery pack arrived in 2016, but there have been questions about whether it is degrading faster than the original 24 kWh pack. The earliest Leafs are also reaching the end of their 8 year battery warranty period. An all-new Leaf was introduced for 2018 and has considerably better range.

    (Image source: Nissan)

  • BMW i3 (2014-2019)

                                        KBB Price

    New     2019                $44,450           Range: 126 miles

                2018                $34,620           Range: 114 miles

                2014                $13,319           Range: 80 miles

    Battery Warranty: At least 70% capacity for 8 years or 100,000 miles

    Summary:

    When BMW introduced the i3 in 2014, it was clear that the German car company wanted to make a statement about its EVs. The i3 had a unique shape and architecture that it didn’t share with any other vehicle in the BMW lineup. Its carbon-fiber reinforced body helped reduce weight while its interior was made largely from recycled and recyclable materials. The i3 also was available with a two cylinder range-extender gasoline engine to help assuage those range anxiety fears. Most of all, the i3 is a BMW—its performance and driving characteristics set it apart from other EVs, new or used.

    (Image source: BMW)

  • Smart fortwo electric drive (2013-2018)

                                        KBB Price

                2018                $24,550           Range: 75 miles

                2018                $14,140           Range: 75 miles

                2013                $3,557             Range: 75 miles

    Battery Warranty: 8 years, 62,000 miles

    Summary:

    The Smart fortwo was the smallest car available in the U.S., and was when the electric drive version was introduced in 2013. With a small 17.8 kWh battery pack, tight dimensions, an incredibly tight turning circle, and just two seats, the fortwo was really designed to be a city commuter. Fortunately, it’s a task at which the Smart excels and that small battery pack can be charged on a Level 2 (220-volt) charger in just a few hours. A cabriolet version is also available for open-air electric motoring. Unfortunately for those of us who like tiny vehicles, Smart stopped selling its cars in North America at the end of 2018.

    (Image source: Smart)

  • Fiat 500e (2013-2017)

                                        KBB Price

    New     2017                $32,795           Range: 87 miles

                2017                $10,101           Range: 87 miles

                2013                $6,648             Range: 87 miles

    Battery Warranty: 8 years, 100,000 miles

    Summary:                                  

    Originally available only in California, the Fiat 500e has found its way across the country, although finding one locally may not always be easy. It’s a subcompact without a lot of rear seat room, and its range is limited, but around town the Fiat 500e is a stylish and fun way to travel. Resale value is obviously low, which is good news if you are in the market for a fun, but cheap, used EV. The 500e was discontinued in 2017.

    (Image source: Fiat)

  • Volkswagen e-Golf (2015-2018)

                                        KBB Price

    New     2018                $37,845           Range: 125 miles

                2018                $24,197           Range: 125 miles

                2015                $11,708           Range: 83 miles

    Battery Warranty: At least 70% capacity for 8 years or 100,000 miles

    Summary:

    The Volkswagen eGolf is based upon the gasoline-powered version of the car—that’s not a bad thing if you are an avid driver as the Golf has long been considered one of Europe’s best handling small cars. The somewhat high price of a used eGolf (relative to other used small EVs) demonstrates the enthusiasm that many have for these cars. VW has announced big plans for electrification of its fleet in coming years, so buying a used eGolf might mark you as an early adopter among fans of the company. 2018 was the last year for the eGolf in the US.

    (Image source: Volkswagen)

  • Chevrolet Spark EV (2014-2016)

                                        KBB Price

    New     2016                $26,000           Range: 82 miles

                2016                $9,658             Range: 82 miles

                2014                $7,726             Range: 82 miles

    Battery Warranty: 8 years, 100,000 miles

    Summary:                        

    The non-electric version of the Chevrolet Spark was one of the least expensive cars in the U.S. and its electric cousin was available for around $20,000 after incentives. The EV version had a robust 140-horsepower which allowed the small car to race to 60 mph in just over 7 seconds. Initially the Spark EV was only available in California and Oregon—at the end of its run it also was available in Maryland.

    (Image source: Chevrolet)

  • Mitsubishi i-MiEV (2012-2017)

                                        KBB Price

    New     2017                $23,845           Range: 62 miles

                2017                $9,765             Range: 62 miles

                2012                $5,069             Range: 62 miles

    Battery Warranty: 8 years, 100,000 miles

    Summary:

    The Mitsubishi i-MiEV is all about its low initial purchase price. What is hard to live with is a range of just 62 miles, less if it is drive hard. Its funky looks and small size scream “EV” which may be a good or a bad thing, depending upon your goals. If you have a short commute, want to get your EV feet wet without spending much money, and want the world to know you are driving an EV, the i-MiEV might be for you. 2017 was the last year for the i-Mev.

    (Image source: Mitsubishi)

  • Tesla Model S (2012-2019)

                                        KBB Price

    New     2019                $86,200           Range: 250 miles

                2018                $75,614           Range: 250 miles

                2012                $34,627           Range: 230 miles

    Battery Warranty: 8 years, 125,000 miles

    Summary:

    The Tesla Model S has had a presence in and impact on the EV market far beyond its sales numbers. Over the years it has been available with a number of different battery pack sizes that can provide a range over 300 miles on a charge, and with single and dual motors for performance up to and including “Ludicrous.” Prices can easily exceed $135,000 for a fully optioned new Model S—for a used one it all comes down to what you can find and how it is equipped. Add in the Tesla Supercharger system of nationwide charging stations and a used Model S is an attractive prospect.

    (Image source: Tesla)

  • Tesla Model X 75D (2016-2019)

                                        KBB Price

    New     2019                $83,200           Range: 237 miles

                2018                $73,545           Range: 237 miles

                2016                $59,179           Range: 237 miles

    Battery Warranty: 8 years, unlimited miles

    Summary:

    Tesla was ahead of the curve when it introduced an electric cross-over utility vehicle (CUV), the Model X. With competition now on the horizon from Jaguar, Audi, Porsche, BMW, Nissan, Hyundai, and Mercedes-Benz, the Tesla Model X still has the specifications to withstand the onslaught. Every Model X has twin electric motors, a whole range of standard features, and unique “Falcon Wing” rear doors that open upward instead of outward. An optional 100 kWh battery in place of the 75 kWh battery can provide a range of up to 295 miles. The Model X can also access the Tesla Supercharger charging network.   

    (Image source: Tesla)

  • Tesla Model 3 (2018-2019)

                                        KBB Price

    New     2019                $45,200           Range: 249 miles

                2018                $46,467           Range: 249 miles

    Battery Warranty: 8 years, unlimited miles

    Summary:

    The Tesla Model 3 is the reasonably priced electric vehicle that Tesla has promised all along. Although its base price is in the mid-$35,000 range, the only versions made so far have been significantly more. In fact, it might be possible to buy a used Model 3 for more than a new one, depending upon which battery and options are involved.

    (Image source: Tesla)

  • Fisker Karma (2012) (Plug-in Hybrid)

                                        KBB Price

    New     2012                $103,000         Range: 50 miles (on battery)

                2012                $35,775 est.    Range: 50 miles (on battery)

    Battery Warranty: none

    Summary:                 

    The Fisker Karma was a beautiful four-passenger sedan that lasted just one year in production. It was a hybrid with a 50-mile battery range and an auxiliary gasoline engine to provide additional range. Since the company went out of business, there is no battery or drivetrain warranty, nor a dealer network, so buying one could be a true risk. On the other hand, used prices for Fiskers seem to be on the rise. A new Fisker venture is underway with a promise to build new EVs in 2019.

    (Image source: Fisker)

  • Chevrolet Volt (2011-2019) (Plug-in Hybrid)

                                        KBB Price

    New     2019                $34,395           Range: 53 miles (on battery)

                2018                $21,060           Range: 53 miles (on battery)

                2011                $9,682             Range: 35 miles (on battery)

    Battery Warranty: 8 years, 100,000 miles

    Summary:

    Chevrolet recognized that “range anxiety” would be a big factor in the acceptance of electric vehicles, so it equipped the Volt with a 1.4-liter four-cylinder gasoline engine that would take over after the battery reached a certain level of discharge and provide an extended range of over 350 miles. It was a smart way to introduce the American public to EVs and the Chevrolet Volt remains a practical alternative to the Nissan Leaf on the used EV market. A second generation of the Volt arrived in 2016, with more battery power and a more usable interior. 2019 will be the last year for the Volt, a victim of the insatiable US market demand for pickup trucks and SUVs.

    (Image source: Chevrolet)

  • Chevrolet Bolt (2017-2019)

                                        KBB Price

    New     2019                $41,895           Range: 238 miles

                2018                $29,166           Range: 238 miles

                2017                $25,006           Range: 238 miles

    Battery Warranty: 8 years, 100,000 miles

    Summary:

    Arriving just ahead of the Tesla Model 3, the Chevrolet Bolt, on paper at least, appears to be just the EV that everyone wanted. Sales have been dismal however, despite the range and performance that the Bolt EV can offer.

    (Image source: Chevrolet)

  • Ford Focus EV (2012-2018)

                                        KBB Price

    New     2018                $29,120           Range: 100 miles

                2018                $19,223           Range: 100 miles

                2012                $6,361             Range: 76 miles

    Battery Warranty: 8 years, 100,000 miles

    Summary:

    Almost unnoticed, the Ford Focus EV has been soldiering along for a six year run that saw it continue to improve. This is definitely a “below-the-radar” kind of car, but if you want to drive an EV, but don’t want your neighbors to know, this car might be for you. The last Ford Focus EV model year was 2018.

    (Image source: Ford)

another-possible-solid-state-lithium-electrolyte-material

One of the most promising ways to increase lithium ion battery performance and safety is through the use of a solid electrolyte. Present commercial lithium ion batteries use an organic liquid electrolyte that provides good mobility of lithium ions between the anode (negative) and cathode (positive) electrodes. The organic solvent is flammable and thus can be a fire hazard should the battery cell become damaged or if it is over charged.

Examining the crystal structure of LTPS is helping materials researchers understand the mobility of lithium ions in solid electrolytes. (Image source: UCLouvain)

Substituting a ceramic or polymer solid electrolyte for the organic solvent would help make the battery safer and, if lithium metal foil is used to replace the current graphite anode, could increase battery performance and storage capacity by 2-3 times. Lithium metal cannot be used as an anode with liquid electrolytes as spikey dendritic lithium crystals form on the metal surface during charging. These crystals can grow large enough to create a short circuit between the anode and cathode, potentially creating a fire hazard.

Better Mobility

So the search is on for a solid material that should allow safer higher capacity lithium-based batteries. The problem is that lithium ions are less mobile in most solid materials than they are in liquid electrolytes, which limits the battery charging and discharging capabilities. That’s why research at Université catholique de Louvain (UCLouvain) in Belgium into a recently discovered material is interesting. According to a news release, the researchers observed that in LiTi2(PS4)3 or LTPS, they measured the highest lithium diffusion coefficient (a direct measure of lithium mobility) ever measured in a solid.

According to the news release, “This lithium mobility comes directly from the unique crystal structure (i.e., the arrangement of atoms) of LTPS. The understanding of this mechanism opens new perspectives in the field of lithium ion conductors and, beyond LTPS, opens an avenue towards the search for new materials with similar diffusion mechanisms.”

Of course, measuring high lithium ion diffusion rates in a laboratory is a long way from building commercial batteries for use in portable electronics and electric vehicles (EVs). While it is easy to overestimate the importance of such developments, the real value in this type of basic research is an enhanced understanding of the mechanisms and physics involved. With greater understanding will come improved materials, which will eventually result in dramatically better batteries.

The Battery Show and Electric & Hybrid Vehicle Technology Expo 2019 conference will take place in Novi, Michigan on September 10-12, 2019. Four days, eight tracks, and over 80 sessions, curated by industry experts will bring battery and electric vehicle technologies into clear focus. In addition, there will be a not-to-be-missed Industry Roundtable that will discuss the future of solid-state lithium batteries.

Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

Drive World with ESC Launches in Silicon Valley

This summer (August 27-29), Drive World Conference & Expo launches in Silicon Valley with North America’s largest embedded systems event, Embedded Systems Conference (ESC). The inaugural three-day showcase brings together the brightest minds across the automotive electronics and embedded systems industries who are looking to shape the technology of tomorrow.

Will you be there to help engineer this shift? Register today!

could-solar-powered-cars-become-practical?

Toyota has placed enough high-efficiency solar cells on a Prius to gain up to 27 miles of driving range during a sunny day. (Image source: Toyota)

The idea of a solar-powered car is an appealing one. The first official solar car race was the Tour de Sol in Switzerland in 1985, and since that time similar races have taken place in the US, Australia, and Europe. The vehicles for such competitions are usually built by universities, often in partnership with car makers and aerospace firms, and are usually highly aerodynamic, single-seat machines having little to do with practical transportation.

Now, Toyota has announced that it is partnering with Sharp and the New Energy and Industrial Technology Development Organization (NEDO) in Japan to test a plug-in Prius hybrid whose power system has been augmented by highly-efficient solar cells. According to a Toyota news release, “The trials aim to assess the effectiveness of improvements in cruising range and fuel efficiency of electrified vehicles equipped with high-efficiency solar batteries.”

Roof Tops

Anyone who is familiar with solar cells will be immediately doubtful about their on-board use to power a vehicle. Photovoltaic (PV) cells are great in stationary applications where, on a rooftop or in a field they can cover a large area and generate electricity, even when the sun is partially hidden behind clouds. In fact, in the early days of electric vehicle (EV) acceptance, it wasn’t uncommon for EV owners to use a rooftop solar array to help charge their vehicles. But finding enough surface area on a vehicle to mount enough solar panels to make a difference is a problem.

Solar panels have been used on some EVs—the original Nissan Leaf for example had an option of a small solar panel on its rear spoiler whose purpose was to maintain the charge of the car’s 12-volt auxiliary battery. Likewise, Toyota has offered solar panels for the roof of its Prius that generated enough power to run a cooling fan in the cabin.

On the Road

Early in 2019, German company Sono Motors announced that it would be going into production with its Sion solar-powered EV. Similar in size to a Nissan Leaf, every flat surface of the Sion is covered in solar cells. The company claims that on a sunny day, the Sion will gain about 19 miles of driving range from the 1.2 kilowatts of output that the solar panels can produce. Although the company plans to eventually sell its Sion worldwide, initially it is concentrating on the European market.

Sharp has developed a high-efficiency solar battery cell with a conversion efficiency of 34 percent (about 10% higher than current commercial cells) and modularized it to create an onboard solar battery panel for Toyota. The solar cell is a thin film about 0.03 mm in thickness. Toyota installed this panel on the roof, hood, rear hatch door, and other parts of its “Prius PHV” to produce a car that could be tested and demonstrated on public roads.

According to the news release, “By enhancing the solar battery panel’s efficiency and expanding its onboard area, Toyota was able to achieve a rated power generation output of around 860 watts.” The result is a system that charges the driving battery while the vehicle is parked and also while it’s being driven. During a full day, Toyota estimates the solar panels will add about 27 miles of EV driving range to the Prius. Because an average person in the US drives around 29 miles per day, the use of solar power for EV charging is beginning to look more practical.

The Battery Show and Electric & Hybrid Vehicle Technology Expo 2019 conference will take place in Novi, Michigan on September 10-12, 2019. Four days, eight tracks, and over 80 sessions, curated by industry experts will bring battery and electric vehicle technologies into clear focus.

Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

Drive World with ESC Launches in Silicon Valley

This summer (August 27-29), Drive World Conference & Expo launches in Silicon Valley with North America’s largest embedded systems event, Embedded Systems Conference (ESC). The inaugural three-day showcase brings together the brightest minds across the automotive electronics and embedded systems industries who are looking to shape the technology of tomorrow.

Will you be there to help engineer this shift? Register today!

copper-sulfide-looks-promising-as-sodium-ion-battery-anode

Schematic model demonstrating grain boundaries and phase interfaces formations for copper sulfide anodes used in sodium ion batteries (Image source: KAIST)

The world keeps looking for cheaper, safer, longer lasting, and more powerful alternatives to lithium ion batteries. Commercial lithium ion batteries have been around since 1991 and have found applications powering everything from personal electronics, to electric vehicles (EVs), to electric power grids.

Sodium ion batteries have shown some promise—sodium ions replace the lithium ions as charge carriers inside the battery during charging and discharging. Sodium is significantly more available and cheaper than lithium. Sodium ion batteries could also be safer—they can be completely drained of their charge during shipping or storage, while lithium ion batteries need to maintain about 30% of their charge providing energy that could ignite a fire if the batteries are somehow damaged.

Commercial lithium ion batteries use intercalation-type materials, such as graphite, to serve as anode (negative electrode) materials that store and release lithium ions between planes of carbon atoms. But graphite anodes have not been viable for high-capacity sodium storage due to their insufficient spacing between the carbon atom layers to accommodate sodium ions.

To build viable sodium ion batteries, a search is on for materials that can achieve higher capacity in the anode. Most such materials unfortunately have large volume expansions and abrupt crystallographic changes when incorporating sodium ions, which lead to severe capacity degradation.

A team at the Korea Advanced Institute of Science and Technology (KAIST) has described in a news release their work using copper sulfide as an anode storage medium for sodium ion batteries. Professor Jong Min Yuk’s team confirmed the stable sodium storage mechanism using copper sulfide that is pulverized and that induces capacity recovery. According to the news release, “Their findings suggest that when employing copper sulfide, sodium ion batteries will have a lifetime of more than five years with one charge per a day. Even better, copper sulfide, composed of abundant natural materials such as copper and sulfur, has better cost competitiveness than lithium ion batteries, which use lithium and cobalt.”

According to Yuk, “Sodium ion batteries employing copper sulfide can advance sodium ion batteries, which could contribute to the development of low-cost energy storage systems and address the micro-dust issue.”

As with so many battery research results, the replacement of lithium ion batteries with commercial sodium ion batteries does not seem like it will happen any time soon, despite the optimism of the Korean team. But progress is continuing and the incentive to improve upon lithium ion batteries is increasing almost daily as a move to further electrification of the transportation system and battery storage for the electric grid reaches primetime.

Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

Drive World with ESC Launches in Silicon Valley

This summer (August 27-29), Drive World Conference & Expo launches in Silicon Valley with North America’s largest embedded systems event, Embedded Systems Conference (ESC). The inaugural three-day showcase brings together the brightest minds across the automotive electronics and embedded systems industries who are looking to shape the technology of tomorrow.

Will you be there to help engineer this shift? Register today!