Solid-state batteries set to shake-up storage

• ‍New research ends doubts about durability of solid-state batteries
• Investment in solid-state battery R&D soaring
• Major focus initially EVs, but stationary storage market now being targeted

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Some of the most exciting innovations in the energy storage sector between now and the end of the decade will come in the area of solid-state batteries.

Indeed, only four months ago, scientists in Australia and Japan made a major breakthrough when they performed tests that showed it was possible to manufacture highly durable solid state batteries, a development that could, among other benefits, drastically reduce the cost of electric vehicles.

Prior to that, solid-state batteries - which use a solid electrolyte as opposed to the liquid or polymer gel found in current lithium-ion batteries - were believed to lack durability. Specifically, it was understood that repeated charging damaged the interface between the electrodes and the solid electrolyte, which caused irreversible changes to the crystal chemistry of the electrodes.

An end to durability doubts?

The durability issue was seen to be the ‘Achilles heel’ of solid-state batteries, which are otherwise considered to offer greater safety than traditional batteries because there is no liquid electrolyte, meaning there is no risk of fire or explosion. In addition, solid-state batteries have a much higher density than traditional batteries, in other words they store more energy per unit volume. Consequently, they are ideal for large-scale energy storage applications where space is limited.

Now a team of researchers from Yokohama National University (YNU) in Japan and New South Wales University (NSWU) in Australia have put an end to doubts about solid-state batteries’ durability. Their study tested the viability of lithium-excess vanadium oxides with a disordered rocksalt structure as high-capacity and long-life positive electrode materials. It found that the materials delivered a “large reversible capacity” (more than 300 mAh g−1) and, crucially, there was no capacity fading after 400 cycles in “all-solid-state batteries with a sulfide-based solid electrolyte”.

The researchers concluded that the finding could drastically reduce battery costs and lead to the development of advanced electric vehicles that fully charge within five minutes.

Solid-state patent applications soaring

The YNU and NSWU study is just one of the recent innovations in solid-state batteries. Indeed, there is evidence to suggest that there is currently much more research and development in the field of solid-state batteries than there is in the lithium-ion battery industry, for example. Data shows that electric vehicle manufacturers, in particular, are ploughing more R&D funding into solid-state batteries than their lithium-ion counterparts.

Statistics from intellectual property law firm Appleyard Lees reveal that priority patent filings for lithium-ion technology around the world (specifically, all countries excluding China) have plateaued during the period 2010-2020, hovering around the 500 to 550 mark every year. In contrast, the number of priority patent filings for solid-state batteries is soaring – there were less than 100 in 2015, but, in 2020, this number had increased to around 400.

The data also shows that car manufacturer Toyota is the company that filed the most solid-state battery priority patent applications in the ten-year period from 2010 to 2020.

Stationary storage now being targeted

But don’t be fooled, solid-state batteries will not be the sole preserve of the electric vehicle industry. In January 2022, it was announced that QuantumScape Corporation and Fluence had signed a “multi-year agreement to introduce solid-state lithium-metal battery technology to stationary energy storage applications”. Upon completion of the deal, the two companies highlighted the huge opportunity presented by the stationary storage market and cited data indicating that stationary energy storage installations are set to grow by more than 2,000% from 2020 to 2030, representing a $385 billion “global market opportunity”. Jagdeep Singh, co-founder and CEO of QuantumScape, remarked: “While we have historically focused on automotive applications, we believe our battery technology is broadly applicable and can play a role in other sectors contributing to a lower-carbon future.”

Meanwhile, in June last year, Iberdrola announced it had taken a stake in solid-state battery company Basquevolt. Iberdrola said Basquevolt would begin production of battery cells in 2027 with the aim of reaching 10GWh capacity, adding that €700 million would be invested and 800 direct jobs would be created. Explaining the reasons behind the investment, an Iberdola statement said that liquid electrolyte lithium batteries were reaching maturity and that the next technological breakthrough to “truly unlock the true potential of energy storage must come from solid-state”.

The Iberdrola statement added that solid-state battery technology is the “only battery technology that meets the most demanding requirements of the automotive sector in terms of performance, which is why it is becoming the strategic focus of the automotive industry”. Iberdrola also made clear its belief that, in comparison to liquid batteries, solid-state batteries were more efficient, had a longer life and experienced less “wear and tear” when recharging.

Solid-state offers ‘best potential’

The era of significant advancements in solid-state battery technology is upon us. As risk management specialist DNV has highlighted, “towards the end of this decade, solid state batteries appear to offer the best potential for a next wave in performance and cost improvements”. Projections indicate that the solid-state battery market will have a compound annual growth rate (CAGR) of 147.8% from 2022 to 2028. A key focus for R&D expenditure in the sector is now the commercialisation of solid-state batteries. In one of the latest developments, it was announced at the beginning of this year that Californian 3D printed solid-state battery technology company Sakuu had selected Porsche Consulting to design the “first-of-its-kind” additive manufacturing gigafactory for commercial production of 3D printed lithium-metal and solid-state batteries.

One of the most innovative sub-sectors of the energy storage industry, the solid-state battery community – buoyed by increasing amounts of R&D funding – is set to make substantial progress in the next few years.

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