12 alternatives to lithium-ion battery storage

• Electric vehicle demand and energy storage deployment set to dramatically increase
  
• Storage dominated by lithium-ion batteries, but lithium supplies could be in jeopardy
  
• What other types of storage could take the place of lithium-ion batteries

The energy storage sector faces a dilemma.

Demand for electric vehicles is set to soar, while numerous forecasts show that energy storage deployment will also grow significantly in the coming years.

While this all sounds like good news for the storage sector, there’s a problem.

Currently, the storage market is dominated by lithium-ion batteries, but the expectation is that lithium supplies will become increasingly hard to access and consequently more expensive.

So what other technologies could potentially step in to make up for a shortfall in batteries caused by a lack of available lithium?

Here’s Energy Storage Report’s guide to 12 alternatives to lithium-ion batteries.

Which technology is your money on?

1. ZINC

Pros: There are different types of zinc batteries - the advantages of zinc carbon batteries include the low cost and high energy density. Aqueous zinc batteries are low cost and more durable than some other types of battery.
Cons: Zinc carbon batteries can be more oxygen-sensitive than other types of battery
What’s the latest? In the last week, aqueous zinc battery company Eos announced it had received orders for a total of 1.1GWh of energy storage from solar developer Bridgelink Commodities.

2. GRAVITY

Pros: More sustainable than other types of storage – for example, US-listed Energy Vault’s system involves lifting and lowering composite bricks or ‘mobile masses’ made from recycled materials.
Cons: Some market observers say gravity storage can involve a multi-crane approach that is too complex and the system requires complicated management processes and algorithms.
What’s the latest? In the last year, gravity-based energy storage company Energy Vault listed on the New York stock exchange. 

3. COMPRESSED-AIR ENERGY STORAGE

Pros: The advantages of CAES include high capacity, high power rating and long-duration storage. 
Cons: The disadvantages include high transportation losses and restrictions caused by the size and the availability of suitable geological locations.
What’s the latest? Earlier this year, Canadian headquartered Hydrostor, which has developed an ‘Advanced Compressed Air Energy Storage’ system, secured $250 million in equity financing from Goldman Sachs. Meanwhile, in May this year, compressed air energy storage company Corre Energy signed a 10-year collaboration agreement with underground energy storage business Geostock

4. ALUMINIUM

Pros: More readily available than lithium and more recyclable. It is also considerably cheaper than lithium – lithium carbonate prices hit $76,700 per tonne this year, whereas aluminium costs a fraction of the price, hovering around the $3,000 per tonne mark this year.
Cons: Aluminium batteries are only in the early stages of development, some scientists argue that aluminium batteries are an unrealistic proposition partly because, in aqueous batteries, aluminium rapidly corrodes.
What’s the latest? Australian based clean-tech company Graphene Manufacturing Group has sent aluminium-ion batteries coin cell prototypes to a number of prospective customers around the world. GMG’s CEO and managing director Craig Nicol said: “We look forward to customer feedback on these prototypes, and to progressing towards the commercialisation of this impressive battery technology." 

5. SALT

Pros: Similar to lithium in terms of its chemical make-up, though sourcing it has less of an impact on the environment. 
Cons: A viable way of developing sodium-ion batteries has not been developed, partly because they would be heavier than lithium-ion batteries – sodium is, in fact, three times heavier than lithium – and less powerful.
What the latest? Market insiders believe there will be an increase in investment in sodium mining and it is anticipated that we’ll see the first prototypes of sodium-ion batteries in the next one or two years. Earlier this year, Swedish-based sodium-ion battery company Altris raised €9.6 million in a Series A funding round to help scale up the company's production of its battery cathode material and conduct further sodium-ion battery research and development.

6. IRON

Pros: Iron is believed to have better ‘redox potential’ than lithium, which means it doesn’t lose its efficiency as quickly. Iron flow batteries have a longer duration than lithium-ion batteries – up to 12 hours, compared to four hours for large scale lithium-ion batteries. Iron flow batteries are non-flammable, non-toxic, and have no explosion risk. Proponents say iron flow batteries offer unlimited cycle life and no capacity degradation over a 25-year operating life.
Cons: Iron flow batteries are much larger than lithium-ion batteries, which means they’re nor really suitable for electric vehicles, though they are feasible for grid storage.
What’s the latest? US iron flow battery company ESS became the first long duration storage manufacturer to go public in 2021 in a move valuing the company at $1.1 billion. In March this year, ESS expanded its operations into Europe.

7. SILICON

Pros: While it wouldn’t replace lithium-ion, silicon could be added to lithium-ion batteries to make them cheaper and longer lasting. Lithium-ion batteries’ have graphite as a key component – the problem is that lithium can slip through gaps in graphite’s stacked carbon layers, which results in a loss of battery storage capacity over time. Making use of silicon instead of graphite has the effect of reducing leakage and creating lighter batteries.
Cons: Critics say silicon-carbon anodes in lithium-ion batteries have a low first discharge efficiency, as well as poor conductivity and poor cycling performance.
What’s the latest? In May this year, Group14 Technologies, a global manufacturer and supplier of advanced silicon-carbon technology for lithium-silicon batteries, announced it had raised $400 million in Series C funding led by Porsche with participation from OMERS Capital Markets, Decarbonization Partners, Riverstone Holdings, Vsquared Ventures and Moore Strategic Ventures.

8. FLOW BATTERIES

Pros: No harmful emissions, long life cycle, low maintenance, able to discharge and recharge at the same time without affecting the cycle life. Electrodes collect current, but are not involved in chemical reactions, meaning they are more durable and stable.
Cons: Low energy density and low charge/discharge rates.
What’s the latest? Last year saw the establishment of industry association Flow Batteries Europe (FBE). While the FBE welcomed the recently proposed EU Batteries Regulation and the Battery Passport, it lamented the fact that the proposal “focuses on batteries with internal storage excluding other important battery technologies, such as flow batteries”.

9. MAGNESIUM

Pros: Batteries made out of magnesium would have a higher energy density, more stability, and a lower cost than lithium-ion batteries, proponents say. Magnesium atoms could release two electrons each during battery discharge, while lithium atoms only release one, meaning magnesium could potentially transfer twice as much energy as lithium. Magnesium batteries have a more robust supply chain.
Cons: Critics highlight efficiency issues as well as electrolyte compatibility. Research is still in the very early stages.
What’s the latest? Earlier this year, chemist Brian Ingram of the Argonne National Laboratory in the US said “there’s a lot of uncertainty, there is still work to be done to provide convincing evidence that energy is actually being stored and released by the metal-oxide positive electrode [in magnesium-ion batteries].” 

10. HEMP

Pros: Boron carbide batteries made out of hemp -  while also using lithium - are cheaper, lighter, better performing and easier to recycle than conventional lithium-ion batteries
Cons: Research is at an early stage and there is uncertainty around the commercial potential.
What’s the latest? Texas-based start-up Bemp Research Corp is understood to have made a boron carbide-type battery made out of hemp, but further testing and investment is needed to assess its commercial potential.

11. SEAWATER

Pros: A plentiful resource – the world’s oceans contain an estimated 180 billion tons of lithium.
Cons: Development is at a very early stage. Evaporating away the water to concentrate the lithium is time and resource intensive.
What’s the latest? A team of researchers at the Karlsruhe Institute of Technology in Germany have developed a prototype battery based on seawater.

12. GLASS BATTERIES

Pros: Eco-friendly, say advocates. Easily sourced materials – key component is glass spiked with sodium ions.
Cons: While engineers at the University of Porto and the University of Texas are working on a glass battery, other members of the science community are sceptical about its potential.
What’s the latest? Some scientists claim that the results of the work are not replicable.