After numerous false starts, bankruptcies and billions of dollars invested, developers of alternatives to lithium-ion batteries for electricity storage believe that a new window of opportunity is opening. This renewed optimism is fueled by maturing battery and nonbattery technologies, some limited commercial successes, demand for longer-duration storage, and growing concerns around the safety and supply chain risks of the incumbent chemistry.

Pointing to a recent major fire at a 2-MW lithium-ion battery system in Arizona, the state’s second such incident, Arizona Corporation Commission member Sandra Kennedy said in an Aug. 2 regulatory filing that the technology carried “unacceptable hazards and risks.” Kennedy urged the state to explore available alternatives “that are far more sustainable and do not have these risks.”

Project owner Arizona Public Service Co., utility subsidiary of Pinnacle West Capital Corp., disclosed Aug. 8 that it would delay its ambitious battery expansion plans to incorporate lessons from the accident. But the utility remains committed to adding energy storage resources, Pinnacle West’s CEO said, perhaps creating an opening for competitors.

“Lithium’s not the only game in town,” said Philippe Bouchard, senior vice president of startup Eos Energy Storage LLC. The New Jersey-headquartered developer of zinc-based batteries has raised nearly $100 million to commercialize its technology, culminating in recent installations in California and North Carolina.

The next step for the company is raising capital for a flagship manufacturing facility. “We have been preparing this scale-up for quite some time,” Bouchard said.

Eos is among dozens of aspiring companies, from upstarts to industrial powerhouses, that are courting investors, utilities, project developers and others to catapult them into competition with lithium-ion leaders LG Chem Ltd., Samsung SDI Co. Ltd., Panasonic Corp. and Tesla Inc. While a few of these efforts have separated from the pack, experts remain skeptical of their near-term chances.

“There are a number of contenders to lithium-ion technology for power storage applications,” said Felix Maire, a senior analyst at S&P Global Platts Analytics. “However, lithium-ion benefits from the massive scale of the electric vehicle market.”

Scientists at the University of California, San Diego have developed an electrolyte they say is compatible with lithium metal anodes, allowing for much greater energy density than current Li-ion battery designs. The new battery has also been shown to function well at temperatures as low as -60 degrees Celsius.

The key innovation is a liquefied gas electrolyte (LGE). Current commercial lithium-ion batteries all use liquid electrolytes, and most researchers are looking into solid materials as the next generation of battery technology. UC San Diego, however, is taking the opposite approach in working with a gas, liquified under pressure, as its electrolyte. The goal is a battery that can take advantage of lithium metal anodes, which could offer high specific capacity, low electrochemical potential and light weight, but can’t work safely or efficiently with conventional liquid electrolytes.

Details of UC San Diego’s LGE work were first published in Science in 2017. At the time, the researchers posited the idea batteries incorporating their electrolyte could power satellites and interplanetary rovers, among other outlandish suggestions.

A new paper, High-Efficiency Lithium-Metal Anode Enabled by Liquefied Gas Electrolytes, published this week in Joule, however, brings the technology down to earth. The paper reports that by optimizing their LGE the researchers were able to create a lithium battery cell which maintained 99.6% efficiency after 500 cycles at room temperature (20 degrees Celsius), and 98.4% at -60.

The team pointed out using a conventional liquid electrolyte with a lithium metal anode has ensured efficiency has not gone beyond 85%, and most liquid electrolytes cease to work entirely at temperatures around -20 degrees Celsius.

Safety first

Another concern about working with lithium metal anodes is the formation of dendrites, which can reduce performance, and in the worst cases lead to short circuits, fires and explosions. UC San Diego reported that with its LGE, lithium particle deposition was “smooth and compact” and porosity of deposition was measured at 0.9%, compared with 16.8% for the same anode in combination with a conventional liquid electrolyte.

Lithium ion batteries may soon be able to charge much faster thanks to what seems like a simple substitution of one mineral for another in the battery’s cathode.

Researchers from the Rensselaer Polytechnic Institute this month announced they had achieved much faster charging rates in lithium ion batteries by replacing the usual cobalt oxide used together with lithium in the cathode with vanadium disulfide.

“It gives you higher energy density, because it’s light. And it gives you faster charging capability, because it’s highly conductive. From those points of view, we were attracted to this material,” said Nikhil Koratkar, the lead author of the study.

The researcher added that improving the electrodes was the way to making lithium ion batteries perform even better.

It seems lithium ion batteries’ dominance will be hard to break with so much work being put into improving these batteries. Koratkar’s team’s work is only the latest example of this work, but there are scores of labs around the world looking for the same ultimate reward: maximizing the performance of the world’s dominant battery technology before a viable alternative really makes it out of another lab.

Recently, the race to reduce charging times for EV batteries specifically heated up as new superchargers came on the scene with few batteries capable of actually using them without getting fried in the process.

Tesla last month opened its first V3 Supercharger station that has a capacity of 250 kW and can add 30 km of range per minute. The company has made its new cars compatible with the new, faster chargers, but Tesla is more of an exception in that it makes its own batteries and chargers.

Pivot Power will collaborate with manufacture and system integrator redT on what is claimed to be the world’s first grid-scale hybrid battery energy storage project to use a combination of lithium-ion and vanadium technologies.

Pivot Power is a relatively new company that has quickly risen to prominence in the UK over the past few months with a plan to deploy 2GW of energy storage and a network of EV chargers.

Pivot will lead a consortium of companies which will develop a £41 million (US$53.89 million) ‘SuperHub’ in Oxford, England, incorporating grid-scale batteries, high speed EV chargers and hundred of ground source heat pumps for local homes.

The project is one of four unveiled by the UK government today (3 April 2019) and will be supported by a £10 million grant from UK Research and Innovation.

The consortium comprises Oxford City Council, Habitat Energy, Kensa Contracting, redT and the University of Oxford.

The entire project has been tagged at £41 million and will establish what the consortium also claims to be the world’s largest commercial hybrid energy storage system at 50MW, incorporating technologies outside of the standard lithium-ion.

RedT, which recently announced a landmark C&I solar-plus-storage programme with Statkraft, will supply 5MWh of flow machines, which will be ‘hybridised’ with a 48MW/50MWh lithium-ion battery system connected at the transmission level.

RedT also confirmed the storage system is to support a local EV charging network consisting of around 100 ultra-rapid and fast chargers.

The hub will meanwhile become one of Pivot Power’s 45 so-called SuperHubs, which combine large-scale battery storage and rapid electric vehicle charging points at convenient destinations for consumers.

Pivot Power unveiled its plans for a multi-billion-pound UK-wide network of battery storage and EV charger installations to much fanfare last year.

Matthew Boulton, COO at Pivot Power, said the project was the start of his company providing the mass charging network needed to “kick-start an electric vehicle revolution” in Oxford, while simultaneously helping the city’s decarbonisation objectives.

Since the first six months of 2018, the benchmark levelized cost of electricity (LCOE) for lithium-ion batteries has plunged 35% to $187/MWh, BNEF says. For projects that have gone into construction in the opening months of this year, the LCOE for solar PV stands at $57/MWh, down 18% from a year earlier. However, recent declines in the LCOE for solar largely occurred in the third quarter of 2018, rather than earlier in the year, as mid-year changes to PV policy in China left the global market awash with surplus modules, BNEF says.

Recent analysis also shows that the benchmark LCOE for offshore wind has tumbled by 24% over the past year, while the onshore wind LCOE has dropped 10%. These “spectacular” declines in cost, BNEF says, suggest that lithium-ion batteries and offshore wind in particular “are now at the center” of the global energy transition.

“There have been staggering improvements in the cost-competitiveness of these low-carbon options, thanks to technology innovation, economies of scale, stiff price competition and manufacturing experience,” says Elena Giannakopoulou, head of energy economics at BNEF. “The LCOE per megawatt-hour for onshore wind, solar PV and offshore wind have fallen by 49%, 84% and 56% respectively since 2010. That for lithium-ion battery storage has dropped by 76% since 2012, based on recent project costs and historical battery pack prices.”

BNEF says the declining cost of lithium-ion batteries is particularly exciting because it creates a wealth of “new opportunities for them to balance a renewables-heavy generation mix.” Technologies such as open-cycle gas turbines, long relied upon by grid operators to handle fluctuations in electricity demand, increasingly must compete with batteries that can offer up to four hours of energy storage, it says.

“Solar PV and onshore wind have won the race to be the cheapest sources of new ‘bulk generation’ in most countries, but the encroachment of clean technologies is now going well beyond that, threatening the balancing role that gas-fired plant operators, in particular, have been hoping to play,” says Tifenn Brandily, energy economics analyst at BNEF.

24M, a US company developing novel lithium battery technology based on semi-solid materials, argues that the remaining runway for lithium batteries – the time during which the technology will continue its rollout as the mainstream choice for both EVs and stationary storage – is plentiful. In other words, the dominant technology of today will likely still be the dominant technology of tomorrow – only better.

Last week Energy-Storage.news reported that by separating the compositional materials used for the catholytes and anolytes of a lithium cell, the team at 24M had achieved an energy density exceeding 350Wh per kg, with a view to establishing a 100MW production line for pilot projects “by the end of this year”.

While admitting that commercialisation remains an estimated two to three years away, 24M, spun out of an MIT laboratory by founder Yet Ming Chiang to investigate solid state and now semi-solid lithium battery materials, claims its latest ‘breakthrough’, Dual Electrolyte Technology, heralds a new era to come for advanced lithium batteries. Andy Colthorpe spoke to some of the company’s leadership team to find out more.

According to Rick Feldt, 24M president and CEO, Rich Chelbowski, CFO, and to senior director of products Joe Adiletta, the Dual Electrolyte tech is one of the “layers of improvements” that the company’s battery manufacturing platforms could add to both LFP (lithium iron phosphate) batteries for stationary storage applications and NMC (nickel manganese cobalt) for mobility applications.

Advanced energy storage projects, mainly using lithium batteries, began to take off after a fairly extended period of demonstrations and pilot projects. Will it be a similar run-in towards commercialisation for semi-solid batteries?

Rich Chlebowski, CFO: For the grid storage space, we’re working on this through one of our partners… they have been in discussion with a number of customers to leverage this output [from our forthcoming 100MW production line]. We have a number of customers that have expressed a lot of interest because of the approach and the potential for very low-cost, high-performance lithium batteries with the semi-solid approach. They have a strong interest in procuring and buying, but more on the demonstration level.

The lithium-ion battery technology, introduced in 1991, has since become the only choice and a standard to power electric cars and smartphones. Many industries are joining the trend to utilize rechargeable battery technology for the purpose of building self-sufficient devices. Over 3 million electric cars around the world are powered by lithium-ion batteries. And more than 36 percent of the world’s population (about 2.1 billion people) depends on lithium-ion batteries to enjoy digital lives.

However, lithium-ion battery technology development has maintained a very slow pace since introduced; many promises of a big leap are either smokescreens or taking too long to happen. This has grossly slowed down the world’s race to an electric future.

Considering the challenges in the use of rechargeable batteries; weight, size and charging, many battery startups are focused on improving the energy density while still making lithium-ion batteries affordable. This quest has led to a completely different paradigm; efficient lithium battery must be lighter, last longer on a single charge and be cheaper.

Fortunately, many startups are coming up with supercharging technology for better performance aside from investing more into building better batteries with improved energy densities and lower costs. Most recent electric cars can travel longer distances and also charge more quickly at supercharger stations. Tesla’s new supercharger stations can add up to 75 miles of range in 5 minutes. That’s not enough, though.

The concept of lithium-ion battery technology
Existing lithium-ion batteries are limited in their physical energy density and material parts, which the new technology seeks to improve. The new lithium-ion batteries are to be more efficient and safer by having no risk of fire if the batteries damage or overheats.

24M, a startup battery company founded as a spin-off from MIT, claims it has made a breakthrough in creating semi-solid lithium-ion battery cells with an energy density exceeding 350Wh per kg.

MIT professor yet Ming Chiang hit upon the idea of mixing active materials in electrolytes together before forming the cell, rather than ‘injecting’ the electrolyte into a slurry, thought to be a much more efficient process for creating cells.

In other words, compositionally distinct catholytes and anolytes are created, kept apart by an ionically conductive, non-permeable separator.

“Unlike a conventional technology where they use a solvent and sort of deposit the material and then throw it all up and then inject the electrolyte at the end, we mix the electrolyte at the beginning,” Joe Adiletta, senior director of products for 24M, said.

“Of course we mix the anode and the cathode separately so we can put a different electrolyte in the anode, called the anolyte or the cathode – catholyte. Typically the separator not only allows the ions to pass but allows the electrolyte to pass. So if you use a traditional separator, eventually the materials will diffuse and you get a homogenous mixture, which is exactly what you don’t want in this design.”

Keeping the anolyte and catholytes separated, Adiletta said, can open up “huge options” on which electrolytes to choose, meaning individual batteries or systems can be tailored to “specific approaches in the battery”. This means the ‘dual electrolyte’ technology can be applied to LFP cells, more commonly used in stationary storage, or NMC cells, higher energy density and typically used for electric cars, to give two prominent examples.

As the race to develop electric vehicles moves to the forefront of the automotive industry, it is vital that battery technology keeps pace with the e-mobility revolution. However, the limited capability of batteries is the primary reason that the growth of electric vehicle R&D has slowed. Lithium-ion batteries are reaching maximum energy density, and it is necessary to develop more powerful batteries that do not have the drawback of flammable liquid electrolytes. Solid-state batteries could be the way forward. They have significant advantages such as:

solid electrolytes;
longer battery life;
stability across a wider span of temperatures; and
no requirement for a cooling system.

What has hindered the growth of solid-state batteries?
Solid-state batteries have been around for decades. However, they have just begun to garner interest from the likes of Robert Bosch and Toyota. Robert Bosch acquired SEEO (a start-up focused on developing solid-state batteries) in 2015 to increase its foothold in the battery technology industry. Since then the automotive giant has taken a U-turn and disbanded its research as the investment was too risky and required higher initial investments than expected. Cost seems to be the primary factor hindering the growth of this technology.

The future of solid-state batteries
Although solid-state battery technology is costly and requires high-risk investments, the following major players are working on its development:

Toyota;
Murata Manufacturing;
Hitachi;
Panasonic;
Hyundai Motor;
NGK Insulators;
LG Chem;
Samsung; and
Union Carbide.

What is more, although the major driving factor of this technology is electric vehicles, it could find application in other fields. TDK, a Japanese electronic battery component maker, is at the forefront of developing small solid-state batteries for electronic devices such as phones, computers and wearables. Looking at patent filing trends, Japan is leading in terms of research. They are followed by China, the United States and South Korea. Japan has the potential to bring this technology forward far earlier than its competitors and regain its foothold in the energy storage sector. However, this is subject to solving the manufacturing problems associated with the production of large solid-state batteries.