Polyrrole-encapsulated Cu2Se nanosheets in situ grown on Cu mesh for high stability sodium-ion battery anode

Abstract

PPy-encapsulated Cu 2 Se nanosheets in-situ grown on the Cu mesh (Cu 2 Se@PPy) acts as a high-performance anode for sodium-ion batteries, capable of delivering a high specific capacity of 293.0 mAh g −1 at 1.0 A g −1 , impressive rate capacity of 263.5 mAh g −1 under 10.0 A g −1 over 2000 cycles. • Cu 2 Se nanosheets were in-situ grown on Cu mesh at room temperature. • PPy coating layer enables robust structure stability and fast charge transport. • Cu 2 Se@PPy as a SIBs anode gives high specific capacity. • Cu 2 Se@PPy as a SIBs anode offers outstanding cycling durability. Copper selenide (Cu 2 Se) features high theoretical capacity and quasi-2D characteristics built by repeating sextuple layers of Se-Cu-Cu-Cu-Cu-Se, making it a fascinating anode for sodium-ion batteries (SIBs). However, it experiences huge volume variation during repeated discharge–charge processes. Here, a productive approach to preserve the structure of Cu 2 Se anode via in-situ coating conductive polymer carbon is proposed. As a demonstration, Cu 2 Se nanosheets encapsulated by polypyrrole (PPy) were anchored on Cu mesh (Cu 2 Se@PPy) and regarded as an electrode material for SIBs. The PPy shell enjoys double functions that improves the electronic conductivity as well as alleviates the significant volume swelling of Cu 2 Se. As a result, Cu 2 Se@PPy gives a satisfactory electrochemical performance, including high specific capacity of 293.0 mAh g −1 at 1.0 A g −1 , impressive rate capacity (263.5 mAh g −1 under 10.0 A g −1 over 2000 cycles). This work describes the uncomplicated approaches available for designing high stability metal selenides anodes for sodium storage.