Synthesis and Fast Exfoliation of Layered GeP Nanosheets for Advanced Li-Ion Batteries

The layered GeP shows great advantages for high-energy Li-ion batteries (LIBs) owing to its large capacity and suitable plateau. However, the morphology of GeP nanosheets is difficult to obtain since recent GeP is always synthesized by a high-energy ball-milled method, resulting in serious amorphous features and failure of smart morphology design for flexible devices. Herein, ultra-thin GeP nanosheets are successfully prepared in a large scale by first synthesizing single-crystal GeP via a typical flux method following a fast electrochemical exfoliation. Compared to tradi-tional ultrasonic or mechanical stripping, such electrochemical exfoliation shows a much higher stripping efficiency and quality to meet the large-scale requirement for battery applications. When served as an anode for LIBs, these GeP nanosheets deliver a large capacity (1150 mA h/g) and superior cyclability (>500 cycles) and rate performance (346 mA h/g at 2000 mA/g) for energy storage. More importantly, benefitting from intrinsic layered structural flexibility, these GeP nanosheets enable self-assembling with reduced graphene oxide (RGO) and carbon nanotubes (CNTs) toward free-standing electrode fabrication without a binder and conductive agent. Consequently, a sandwich-like GeP@RGO@CNT hybrid electrode is well-designed, enabling a high capacity (870 mA h/g) and good performances for LIBs as well. This fast exfoliation of GeP nanosheets and free-standing electrode construction can be easily extended to other layered materials toward advanced energy storage.

Automated summary

Ultra-thin GeP nanosheets were successfully prepared in a large scale through fast electrochemical exfoliation, with high stripping efficiency and quality. These GeP nanosheets exhibited large capacity and excellent performance as anode materials for LIBs, and could self-assemble with RGO and CNTs to form free-standing hybrid electrodes.