Photoinduced Rechargeable Lithium-Ion Battery.

Lithium-ion battery (LIB) design is the predominant technology to power portable and mobile electric devices/equipment. Fast charging and self-powering of LIBs are significant but challenging features to be addressed for meeting the fast-paced society and emerging demands. Herein, we report a rational photorechargeable lithium-ion battery (photo-LIB) design using LiVO as a photocathode by directly modifying a commercial LIB without using any additives, which works in both photoassisted fast charging and photo-only charging modes. The photo-LIB attains a high specific capacity of 185 mAh g in as fast as 5 min under illumination, an enhancement of 270% referring to that in dark. Under the photo-only charging mode, the device achieves a highest full-spectrum photo-energy conversion efficiency of 9% so far, demonstrating a highly efficient self-powering mode. We reveal that the improved performance of photo-LIB is due to reversible vanadium intervalence charge transfer and Li insertion/deinsertion in LiVO under illumination.