Solid-state Lithium batteries: the next generation

Money is pouring into research into solid-state lithium batteries (SSBs) which promise to leapfrog existing lithium-ion battery technology.

A battery consists of three parts: a cathode, an anode, and the electrolyte. The cathode releases electrons which are then transported through the electrolyte and received by the anode. Current lithium-ion batteries use a graphite-silicon anode with a liquid electrolyte. Solid-state batteries replace the liquid with a solid electrolyte (SE), normally in a thin film — made from either an oxide, sulfide, a halide or a polymer.

Solid-State Battery

Metal-halides are gaining more attention due to their excellent compatibility toward oxide cathode materials, acceptable ionic conductivity and wide electrochemical stability. (Science Direct)

SSB Advantages

Solid-state batteries promise greater energy density, better performance at low temperatures, greater safety, faster charging, longer range, and longer battery life.

Enhanced thermal performance is expected to improve operation at low temperatures — a key weakness in cold climates. Safety is also improved by the solid electrolyte which is unlikely to leak if the battery casing is punctured — for example in a car accident — reducing the risk of a fire.


There are still problems that have to be solved. A key stumbling block is the anode.

Lithium-metal anodes show promise but development has been plagued by dendrites which accumulate on the anode and rapidly reduce its effectiveness. Dendrites are also likely to cause a fire if they grow to the point that they pierce the barrier between the anode and the cathode.

Other developers have opted for silicon anodes but these present a different problem. Silicon is highly conductive, making it suitable for use in battery construction, but the silicon expands and contracts with each charging cycle, causing deterioration over time.

State of Progress

Toyota, one of the leading developers, has pushed back the planned introduction date for their new SSBs until 2028.

Another developer, California-based QuantumScape (NYSE:QS), seems to be making progress:

In January, Volkswagen announced successful testing on a solid-state battery developed by QuantumScape achieved more than 1,000 charging cycles and maintained 95% of its capacity. (The Guardian)