Metal-organic framework derived in-situ nitrogen-doped carbon-encapsulated CuS nanoparticles as high-rate and long-life anode for sodium ion batteries

摘要

Transition metal sulfides (TMSs) have been considered as the most promising candidates for anode materials of sodium-ion batteries (SIBs) due to their high theoretical specific capacity. However, large volume expansion caused by conversion reaction during sodiation-desodiation processes generally leads to poor structural stability. Herein, metal-organic framework (MOF)-derived in-situ nitrogen-doped partially graphitized carbon-encapsulated CuS nanoparticles (CuS@N-C) has been successfully prepared via a two-step process of carbonization and sulfidation. The preparation strategy using Cu-MOF as precursor realizes in-situ encapsulation of CuS into nitrogen-doped carbon matrix, simultaneously endowing the CuS@N-C with high conductivity and rigid structure protection. As a result, the CuS@N-C shows an excellent electrochemical properties as an anode of SIBs: delivering the satisfying rate capability of 259.4 mAh g(-1) at 5 A g(-1) and exhibiting the high reversible capacity of 300.2 mAh g(-1) after 1200 cycles at 5 A g(-1) with an ultra-low capacity decay of 0.0035% per cycle. This study proposes an effective strategy to develop novel anodes with excellent cycling and rate properties for SIBs by encapsulating active nanoparticles into carbon matrix. (C) 2020 Elsevier B.V. All rights reserved.