Decahedron Cu1.8Se/C nano-composites derived from metal–organic framework Cu–BTC as anode materials for high performance lithium-ion batteries

Abstract

Transition metal selenides (TMSs) are potential high-power lithium-ion batteries (LIBs) electrode materials because of its considerable theoretical capacity and high electrical conductivity. However, through the electrochemical conversion reaction, the structure of TMSs may be easily destroyed due to its terrible volume effect, which thereby greatly reducing the electrode’s capacitance and cycle life. In this paper, we have synthesized carbon-encapsulated Cu1.8Se decahedron nano-composites (Cu1.8Se@C) using a metal–organic framework Cu-BTC as template. When applied in anode for LIBs, due to the synergistic effects of tiny copper selenide, integral porous decahedron and exceptional carbon-encapsulated structure, the Cu1.8Se@C nano-composites exhibit improved specific capacity, superior rate capability and exceptional cycling stability. The initial discharge specific capacity of Cu1.8Se@C-500 °C is 1186.6 mAh g−1 at a current density of 0.1 A g−1, and after 200 cycles, the specific capacity drops to 824.4 mAh g−1. What’s more, at a current density of 1 A g−1, the Cu1.8Se@C-500 °C electrode still possesses a considerable specific capacity of 320.3 mAh g−1 after 1000 cycles. In light of our findings, we propose a metal–organic frameworks (MOFs) templates strategy to synthesize in situ carbon-encapsulated TMSs electrode materials with outstanding electrochemical performance for LIBs.