The mounting challenge of lithium-ion battery recycling should be addressed at the design stage. To date, though, manufacturers have focused more on safety, power density, and cyclability.

Lithium-ion battery recycling researchers from the universities of Leicester, Newcastle and Birmingham; The Faraday Institution; the ReCell Center and the Argonne National Laboratory have examined product design and published their findings in the paper The importance of design in lithium-ion battery recycling – a critical review, published in Green Chemistry.

“To create a circular economy for any material, it is important to have few components, a lower cost for the secondary process [recycling] than the primary process [raw material extraction], a simple purification flowsheet, valuable components, and a collection and segregation mechanism,” wrote the authors. “It also helps when the material has a significant environmental impact if not recycled, as this tends to mandate its recycling.”

Lead-acid

Lead-acid batteries fulfill those design requirements, which explains a collection rate of near 100% in Japan, the U.S. and most of Europe and a recycling regime which recovers more than 98% of the total mass of the batteries. Lead-acid batteries are straightforward in design, with a polypropylene casing, an electrolyte, and two electrodes, made from lead and lead oxide. Separating components by density is relatively simple given lead and polypropylene have values of 11.3 and 0.9g/cm-3.

The similar density values of the cathodes and current collectors in lithium-ion batteries renders a similar approach impossible. Therefore, lithium-ion devices require approaches such as redox reactions, solubility, or exploiting electrostatic and magnetic properties to separate the materials of which the cells are made up.

Lack of labeling is another significant obstacle to an effective recycling regime. Unlike lead-acid batteries, lithium devices show a variety of chemistries and architectures, such as NCA, NMC, LMO, LCO, and LFP batteries, all of which can combine in different chemistries. Cells can also come in pouch, prismatic, or cylindrical form before being soldered together into modules and combined in the pack.

In the first part of this series of articles, an overview of the flow batteries characteristics has been provided, extrapolated from IDTechEx’s recent report “Redox Flow Battery 2020-2030: Forecast, Challenges, Opportunities”. In this second article, a more detailed analysis about the different chemistries will show the main RFB technologies currently available or under development, beginning with the most adopted and investigated Redox Flow Batteries (RFB), the Vanadium Redox Flow Batteries (VRFB).

Initially studied by NASA, and further developed in 1980’s by the research group led by Maria Skyllas-Kazacos at New South Wales in Australia, the Vanadium redox flow battery (VRFB) are today the most studied and manufactured technology within the redox flow battery technology. Besides different type of RFBs, the vanadium technology (and similarly the All-Iron RFB) employs the same electroactive species (vanadium) in both electrolytes, with different oxidation states. The following reactions take place during charge and discharge of VRFBs:

The low round-trip efficiency and the high cost of vanadium (directly affecting the cost of electrolyte) are two of the main VRFBs’ drawbacks. The electrolyte alone accounts for 30% to 40% of the overall technology cost. To reduce the effect of vanadium cost on the overall system, an increasing number of companies started collaborations with vanadium mining companies. The aim of the collaborations is to improve the vanadium electrolyte performances by increasing the vanadium concentration (moles of Vanadium per litre of electrolyte). This would allow reaching the higher energy density of the battery, and the reducing of the cost.

According to the investigation conducted by IDTechEx, it was clear that some mining companies themself are interested in the VRFB technology. This is the case for the South African mining company Bushveld Minerals. Bushveld Minerals is in fact actively promoting the adoption of vanadium flow battery all over Africa. Outside of the African countries, Bushveld backed the merge between two VRFBs manufacturers (the English redT and the American Avalon Battery), and in 2019 announced to acquired a consistent share of Enerox-CellCube, previously known as Gildemeister AG.

Although the Vanadium technology dominated the flow battery scenario, over the last years a growing number of other redox flow batteries are populating the market.

In line with the European Green Deal, the ‘Next Generation EU’ package recognizes hydrogen for its ability to bolster the long-term objectives of the European Union and the essential role it can play in achieving climate neutrality.

Economies across the world have begun engaging with hydrogen. Many governments have created generous subsidies to pursue hydrogen as a way of diversifying their energy sources.

Still, lithium-ion remains the dominant energy storage technology for the wider industrial sector and is expected to dominate the markets. Investments from EU’s Green Stimulus through the IPCEI Initiative to support innovations to battery value chain underline how important lithium-ion technologies will become. The project supports the development of innovative and sustainable technologies for lithium-ion batteries (liquid electrolyte and solid-state) that last longer, have shorter charging times, are safer, and more environmentally-friendly than those currently available. Innovation will also specifically aim at improving environmental sustainability across all segments of the battery value chain. It aims to reduce the CO2 footprint and the waste generated along with the different production processes as well as develop environmentally friendly and sustainable dismantling, recycling, and refining in line with circular economy principles.

Lithium is leading the innovations

The global lithium-ion battery market has experienced a period of exponential growth in recent years and Data Bridge Market Research expects the lithium-ion EV market to continue growing at an annual rate of 15.70% in the forecast period of 2020 to 2027. The growth of the market is attributed to the growing demand for lithium-ion batteries in a number of applications (electric vehicles, robots for warehouse, e-marine & e-transports), which provide lower maintenance requirements, longevity, and are a more sustainable solution in comparison to fuel.

For smaller vehicles, in particular, for the motive power industry, the technological developments of lithium-ion mean that repair and maintenance efforts are considerably reduced. In most cases, maintenance is not necessary at all, equating to an important reduction in the annual total cost of ownership compared to other technologies providing significant savings on labor costs of maintenance staff. They also notably reduce idle time through speed of charging and the advantages brought about by opportunity charging – which allows a battery to be charged several times during a work-cycle with no effect on battery service life. This is particularly important for industries that rely on efficiency, such as logistics.

In this first part of a series of articles from IDTechEx, an overview of the flow batteries characteristics is provided, extrapolated from IDTechEx’s recent report “Redox Flow Battery 2020-2030: Forecast, Challenges, Opportunities”.

While Li-ion batteries are dominating the stationary energy storage sector, a growing number of companies are developing different technologies to be competitive in the near future and bring to the market a more competitive energy storage system. Among the Li-ion batteries competitors, the Redox Flow Battery (RFB) is one of the main competitors currently approaching the market.

Recently IDTechEx performed an in-depth analysis of redox flow batteries from a technical and market aspect, evaluating their potential to address the evolving stationary energy storage market.

While it is clear that Li-ion batteries will dominate the scene for the near future, this promising competitor has already shown its capability to gain its portion of the energy storage market, pushing the ES industry toward new horizons.

The extensive volumetric (Wh/L) and gravimetric (Wh/kg) energy density of Li-ion batteries make this technology well suited to address the EV market. Pushed by the cost decreasing from the EV market, this technology started to also be competitive in the stationary energy storage market, for front-of-meter (FTM), and behind-the-meter (BTM) applications. The capability to address the complete spectrum of the energy storage market is translated in a power range of few kWs for behind-the-meter use, to MWs power output for front-of-meter applications.

These properties make Li-ion batteries extremely competitive and difficult to be challenged, although other technologies are starting to appear in the market.

French company Nawa technologies says it’s already in production on a new electrode design that can radically boost the performance of existing and future battery chemistries, delivering up to 3x the energy density, 10x the power, vastly faster charging and battery lifespans up to five times as long.

Nawa is already known for its work in the ultracapacitor market, and the company has announced that the same high-tech electrodes it uses on those ultracapacitors can be adapted for current-gen lithium-ion batteries, among others, to realize some tremendous, game-changing benefits.

It all comes down to how the active material is held in the electrode, and the route the ions in that material have to take to deliver their charge. Today’s typical activated carbon electrode is made with a mix of powders, additives and binders. Where carbon nanotubes are used, they’re typically stuck on in a jumbled, “tangled spaghetti” fashion. This gives the charge-carrying ions a random, chaotic and frequently blocked path to traverse on their way to the current collector under load.

Nawa’s vertically aligned carbon nanotubes, on the other hand, create an anode or cathode structure more like a hairbrush, with a hundred billion straight, highly conductive nanotubes poking up out of every square centimeter. Each of these tiny, securely rooted poles is then coated with active material, be it lithium-ion or something else.

The result is a drastic reduction in the mean free path of the ions – the distance the charge needs to travel to get in or out of the battery – since every blob of lithium is more or less directly attached to a nanotube, which acts as a straight-line highway and part of the current collector. “The distance the ion needs to move is just a few nanometres through the lithium material,” Nawa Founder and CTO Pascal Boulanger tells us, “instead of micrometres with a plain electrode.”

This radically boosts the power density – the battery’s ability to deliver fast charge and discharge rates – by a factor of up to 10x, meaning that smaller batteries can put out 10 times more power, and the charging times for these batteries can be brought down just as drastically. Nawa says a five-minute charge should be able to take you from 0-80 percent given the right charging infrastructure.

California officials expect zinc energy-storage technologies to help the state attain 100-percent clean energy by 2045, proving cheaper and safer than lithium-ion while holding a charge longer.

“Some of them are looking for 25 to 50 hours of storage,” said Mike Gravely, research program manager at the California Energy Commission.

“Some of them are looking to provide residential homes the storage they need to ride through these PSPS (public-safety power shut-off) events that California has, or to provide the reliability and resiliency that a home should have, and they’re in the size that they would fit in your garage, or they would fit something about the size of your outside air conditioner.”

California recently invested $16.8 million in energy-storage technologies beyond lithium-ion, many of which employ zinc.

“If you look past lithium ion, probably zinc is the next metal that’s the most popular for energy storage, and it it does appear to be able to provide performance equal to or better than lithium if given a chance,” Gravely said in a webinar hosted by the Clean Energy States Alliance. “So we have projects where we’re doing zinc batteries at the residential level, the commercial level, and the industrial level.”

The state plans to install 2,400 megawatts of energy-storage through 2023, about 90 percent of which are based on lithium-ion technologies. But state officials estimate they will need another 20,000 to 30,000 MW of energy storage by 2045.

Lithium-ion dominates the short-term outlook largely because investors will support it, Gravely said, and investors have been reluctant to venture beyond lithium-ion. The grants—going to companies including E-Zinc, Salient Energy and Anzode Energy—are designed to move alternative technologies out of the laboratory and into the field or into commercial use where they can prove their mettle.

California needs batteries. When California is on fire, it needs batteries that can keep a home, a hospital, a fire station, a senior center running longer than the four-hour standard of lithium-ion.

“What’s happened that’s brought this to bear has been the wildfires and the contingency issues we have in the PSPS (public-safety power shut-off) events,” said Mike Gravely, research program manager for the California Energy Commission.

“In November of last year over two million resident people in California were impacted by wildfire PSPS events” in which utilities shut down portions of the grid to prevent equipment from sparking fires during flammable conditions. “The average short outage was 11 hours, and some of it went as high as three to five days.”

During those outages, senior centers and hospitals have relied on diesel generators to supply electricity for critical-care equipment, but during wildfires, diesel fuel can also be hard to come by.

“Microgrids are a big topic,” Gravely said in a webinar hosted by the Clean Energy States Alliance, “and energy storage is a key element of all micro grids.”

What California needs has outsized significance in the energy-storage industry. The state expects to install 2,400 megawatts of energy storage in the next two years, a market-driving number that is, even so, a mere fraction of the 20,000 to 30,000 MW Gravely expects the state to need by 2045.

Lithium-ion’s seeming limitation to four hours can also be traced to California. It’s not so much a feature of the technology as a feature of California’s market, Gravely explained. The grid operator there reimburses storage resources that supply a minimum of four hours and, he said, “that’s what’s been driving most of our systems.”

But California officials believe other technologies can outperform lithium-ion on cost, reliability and safety while providing power for longer durations.

“Part of the microgrid research we’re doing (involves) 45 micro grids,” Gravely said. “Probably at least 40 of those are actually operating with lithium-ion technology, so it’s not like we’re not evaluating and researching lithium-ion technology. We are, but the challenge is that we’re trying to broaden the horizon of options as we go forward.”

A community choice energy provider run by the San Francisco Public Utilities Commission in California has signed contracts for battery storage with EDF Renewables and NextEra Energy totalling 260MWh, to be deployed in combination with solar PV.

San Francisco Public Utilities Commission is the provider of water to the City of San Francisco and other parts of the Bay Area in California but also provides hydroelectric and solar energy in the Hetch Hetchy Valley of the famous Yosemite National Park – as well as providing power to San Francisco homes and businesses through its community choice programme, CleanPowerSF.

Community choice utilities providers, active in a handful of US states, are non-profit entities that enable customers to choose where their power comes from and through which sources, while still being able to rely on large investor-owned utilities’ infrastructure to transmit and distribute that power. The groups have been active in the past year or so in inking contracts for clean solar PV coupled with battery storage that makes the power dispatchable and reliable, nowhere more so than in California.

CleanPower SF serves about 380,000 customers with electricity. It has just signed two separate contracts: one with a NextEra subsidiary to deliver a 20MW solar PV project combined with a 60MWh battery storage system and the other with EDF Renewables North America for a 200MWh battery storage system to be coupled with a 100MW solar PV plant that is already under construction by EDF. The projects will be CleanPowerSF’s first to add battery storage to its generation portfolio.

Solar-plus-storage to help bring grid reliability to customers amid ‘rolling blackouts and other power uncertainties’

EDF Renewables, itself a subsidiary of France-headquartered utility major EDF Group, has done around 16GW of renewables projects in North American markets and looks after another 11GW under service contracts. The company claims the 200MWh project award from CleanPowerSF brings its battery storage portfolio to be constructed in the US by 2023 to 1.5GWh. Also contributing a significant chunk of capacity to that pipeline is a 200MW solar PV project in Nevada which will utilise 180MW / 720MWh of battery storage.

It will be in the interests of more or less everybody involved in the “broader lithium-ion battery supply chain” to establish effective recycling ecosystems, according to an analyst with IHS Markit.

Recycling was among the big topics covered at this week’s Energy Storage Virtual Summit hosted by our publisher Solar Media’s events division. The majority of lithium-ion batteries used in stationary energy storage for solar, back up power or grid-balancing services have only been in operation for a relatively short amount of time, but consideration is being made for the future when a large number of systems begin reaching their end of life (EOL).

Chloe Holzinger, a senior analyst for energy storage at the research company, said during a presentation on the present and future prospects for recycling lithium batteries that stakeholders involved in everything from raw materials to component and equipment production, as well as end users, will have a keen interest in the possibilities for recycling.

Raw materials and cathode producers in particular might see recycling as a potential extra revenue stream, while their direct competitors might be recyclers that also begin to produce cathode materials directly. Given the low volumes of batteries available for recycling ahead of 2030, policy and regulations to encourage and foster recycling ecosystems would be helpful, Holzinger suggested.

Holzinger’s colleague at IHS Markit, Youmin Rong, who is a senior analyst in clean energy technology, said that the company is forecasting that 600GWh of batteries will reach their EOL by 2030 across electric vehicle, grid storage and portable electronics segments, and more than 2.5TWh by 2050.

The growth in the automotive sector’s demand for batteries alone will make it “essential to have a recycling industry,” Youmin Rong said, adding that since electric cars and stationary energy storage systems will require cells with vastly more capacity than the types of cells found in portable electronics like smartphones, an “an industry of recycling for large-scale lithium-ion is needed today more than ever”.