Solid-state batteries: a new era of energy storage

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.

Solid-state batteries could be a much-needed breakthrough in battery technology but they are still far from marketable. High manufacturing costs are not the only barrier; research still needs to be carried out to find a suitable cathode and anode, as well as solid electrolytes. Research is primarily focused on identifying solid electrolytes with high ionic conductivity, high electrical resistance and compatibility with the cathode and anode material and with no built-in field at the cathode/electrolyte or electrolyte/anode junction that could be detrimental to lithium-ion diffusion across the junction.

Comment

Solid-state batteries have numerous advantages over current batteries but many obstacles need to be overcome if they are to realise their full potential. Following this, we will see huge growth across various industries, not just electric vehicles and consumer electronics but also grid energy storage, medical devices and avionics. It will also be interesting to see how this technology could transform devices in the Internet of Things.