Optoelectronic and photo‐charging properties of CH3NH3PbI3/LiFePO4 system

Summary The photo‐responsive capability of lithium battery materials is a prerequisite to realize new‐generation light‐weight photo‐rechargeable batteries. However, the photo‐charging property is not available for common battery electrode materials such as LiFePO 4 . In this manuscript, we provide evidence that the halide perovskite material CH 3 NH 3 PbI 3 is able to activate the photo‐charging properties of the lithium‐ion battery electrode material LiFePO 4 . The photoelectrochemical measurement demonstrates that the photo‐responsive property of the CH 3 NH 3 PbI 3 /LiFePO 4 composite is significantly improved; the photo‐induced signals are neither observed in the individual halide perovskite nor the lithium battery material tested under the same condition. The first‐principles calculations reveal strong interactions between the CH 3 NH 3 PbI 3 layer and the LiFePO 4 layer via the coordination between the Lewis acid and Lewis base species; this forms a heterostructure that assists the photo‐charging process. We propose that the combination of halide perovskite materials and lithium battery electrode materials is a viable way to achieve light‐weight photo‐batteries. Suggestions to address the stability and voltage issues of the halide perovskite‐based hybrid systems toward the photo‐battery application are provided. This study facilitates the fundamental understanding of the integrated photo‐rechargeable battery materials and highlights the importance of halide perovskite materials for the lithium‐ion and photo‐rechargeable batteries.