Powering Electric Vehicles With Solid-State Batteries

Solid-state batteries are significant because the solid electrolytes enable a few technologies that might make batteries more energy-dense, which is necessary for modern electric vehicles to have a greater range or last longer.

Fremont, CA: The adoption of electric vehicles and the constant growth in portable electronic devices are becoming more and more relevant to solid batteries. Solid-state batteries depend on a solid electrolyte membrane with positive and negative electrode materials.

To permit charge or discharge, ions travel using an ion-conductive solid matrix. Solid-state batteries are significant because the solid electrolytes enable a few technologies that might make batteries more energy-dense, which is necessary for modern electric vehicles to have a greater range or last longer.

For example, while charging a regular lithium-ion battery, a reaction occurs between the liquid lithium salt electrolyte and the carbon electrode, forming a layer that helps protect the carbon and stops the two components from reacting further. This is named a solid electrolyte interface (SEI layer). This very thin and fragile layer generally determines the battery’s durability.

Tokyo Tech scientists addressed one of the major drawbacks of all-solid-state batteries by developing low-resistance batteries at their electrode/solid electrolyte interface. While the devices they produced were promising and, in some aspects, much better than conventional Li-ion batteries, the mechanism behind the decreased interface resistance was unclear.

The buried interfaces in solid-state batteries could barely be analyzed without damaging their layers. Therefore, they presumed that crystallinity played a key role in defining interface resistance at the electrode-electrolyte interface. Two different all-solid-state batteries consisting of electrode and electrolyte layers were manufactured using a pulsed laser deposition technique to prove this.

Through the X-ray crystal scattering test, scientists determined crystallinity present at electrode-electrolyte in one of the batteries made with the help of the pulsed laser deposition technique. The team finalized that a highly crystalline electrode-electrolyte interface produced low interface resistance and a high-performance battery.

IMEC, one of the major R&D and innovation hubs, has prepared a prototype battery using a solid nanocomposite electrolyte with high conductivity of up to 10 mS/cm and is likely to increase this capacity.

The prototype battery acquired a 200 Wh/litre of volumetric energy density at a speed of 0.5C. However, li-ion has still untapped the potential for advanced performance and cost reduction improvements—a solid-state battery must be benchmarked with a mobile target. In addition, major manufacturing companies are working toward the large-scale commercialization of solid-state batteries, further boosting the market for these batteries in the future.