Enhancing the Rapid Na⁺-Storage Performance via Electron/Ion Bridges through GeS₂/Graphene Heterojunction

Abstract

Hybridizing carbonous matrix into metal sulfide is confirmed as an effective strategy to enhance electrode conductance and structure stability. However, a comprehensive understanding of the interface reaction mechanism between active materials and carbon substrate is still urgently needed. Based on the band energy theory, a route to enhance the rate ability for electrode is exploited on regulating interfaces of substrates/active heterojunction. Herein, the highly stable Na⁺-storage performance of GeS₂/3DG is delicately designed, where the hierarchical structure is enabled by uniformly overcoating GeS₂ nanograins with graphene matrix. Different from the widespread doping route of active materials for fast ion transfer, we focus on the effects of interface regulation on the high-rate Na^- ion-storage performance of substrate/active materials. Here, a well-designed interface of the C-Ge bond at the heterointerface induced by hierarchical GeS₂/graphene heterojunction is pioneeringly explored, which can result in a fast electron transfer by reducing electron gathering polarization. More importantly, defects in graphene can alleviate the polarization aroused by ion concentration, which not only offers anchoring/doping sites for C-Ge bond but also provides extra ion channels for Na-ion transportation into GeS₂. This interface regulation of constructing metal-carbon bonds will shine light on the reaction kinetics and interface stability and contribute to the fundamental understanding of interface reaction mechanisms for metal sulfide anode materials.