A new study led by researchers from the National Institute of Materials Science and Technology in Japan shows that in solid electrolytes, silicon anodes composed of industrial silicon nanoparticles prepared only by spray deposition have excellent electrode performance. This method is a cost-effective atmospheric technology, so the results of the researchers indicate that in the near future, low-cost and large-scale production of large-capacity negative electrodes for all-solid-state lithium batteries will be possible.
The theoretical capacity of silicon can reach 4200 mA / g, which is 10 times larger than the capacity of graphite commonly used as an active negative electrode material on commercial lithium batteries. Replacing traditional graphite with silicon can greatly extend the mileage of electric vehicles per charge, but silicon will undergo huge capacity changes during the lithiation and delithiation, that is, during charging and discharging, which hinders its practical application in batteries .
In traditional liquid electrolytes, it is necessary to use a polymeric binder to fix the active material particles in the electrode together and maintain their adhesion to the metal surface. The continuous capacity change of silicon will cause the particles to separate, lose active materials, and finally cause a continuous capacity loss. In solid-state batteries, the active material is placed between two solid-state components, namely the solid electrolyte separator and the metal current collector. The actual area capacity of the sputter-deposited pure silicon thin film exceeds 2.2 mAh / cm2, showing good cycle stability and high rate discharge capacity in the solid electrolyte. Nonetheless, the cost-effectiveness and industrial scalability of all-solid lithium battery anodes remain a huge challenge.
Researchers from the National Institute of Materials Research team in Japan have adopted another synthetic method to obtain a high-performance anode for commercial solid-state lithium nanoparticle batteries. They found that nanoparticles have a unique phenomenon in solid-state batteries: after lithiation, they undergo volume expansion, structural compaction, and obvious coalescence in the limited space between the solid electrolyte separator layer and the metal current collector to form a A continuous membrane is similar to the membrane prepared by evaporation. Therefore, the negative electrode composed of nanoparticles prepared by the vapor deposition method has excellent electrode performance, which was previously observed only on thin-film electrodes deposited by sputtering. Spray deposition is a cost-effective atmospheric technology that can be used for large-scale production.
Therefore, these findings will pave the way for low-cost and large-scale production of large-capacity negative electrodes for all-solid-state lithium batteries.