Ultra-large sized siloxene nanosheets as bifunctional photo-catalyst for Li-O2 battery with superior round-trip efficiency and extra-long durability.

Abstract

Developing new optimized bifunctional photocatalyst is of great significant for achieving the high-performance photo-assisted Li-O 2\xa0 batteries. Herein, a novel bifunctional photo-assisted Li-O 2 \xa0 system is constructed by using siloxene nanosheets with ultra-large size and few-layers due to its superior light harvesting, semiconductor characteristic, and low recombination rate. An ultra-low charge potential of 1.90 V and ultra-high discharge of 3.51 V have been obtained due to the introduction of this bifunctional photocatalyst into Li-O 2\xa0 batteries, and these results have realized the round-trip efficiency up to 185%. In addition, this photo-assisted Li-O 2 batteries exhibits a high rate (129 % round-trip efficiency at 1 mA/cm 2 ), a prolonged cycling life with 92 % efficiency retention after 100 cycles, and the highly reversible capacity of 1170 mAh/g at 0.75 mA/cm 2 . This work will open the vigorous opportunity for high-efficiency utilization of solar energy into electric system.