MCr2Se4(M = Cu, Ni, Fe)/C composites derived from metal-organic frameworks as novel anode materials for lithium-ion batteries

Lithium-ion batteries (LIBs) have attracted widespread attention because of their advantages such as high energy density, lightweight, and environmental friendliness. The search for high-performance anode materials is an important research direction. Metal selenides anode materials with high theoretical capacity have been highly valued. Herein, MCr₂Se₄(M = Cu, Ni, Fe)/C composites were prepared via simple hydrothermal and vacuum solid-phase method and used as novel anode materials for LIBs. The outer carbon skeleton not only prevents the aggregation of metal selenide particles, but also further constructs a conductive network to achieve fast charging. Meanwhile, the MCr₂Se₄/C composites have a large surface area and porosity, which not only increases the contact with the electrolyte, shortens the diffusion path of ions and electrons, but also reduces volume expansion during the lithiation process. All the synthesized CuCr₂Se₄/C, NiCr₂Se₄/C, and FeCr₂Se₄/C have excellent electrochemical performance as anode materials for LIBs. Specifically, the initial discharge specific capacity of FeCr₂Se₄/C is 870.87 mAh g⁻¹ (at 0.1 A g⁻¹), the specific capacity can maintain at 762.51 mAh g⁻¹ after 200 cycles, and it can still achieve a stable specific capacity of up to 501.49 mAh g⁻¹ at 5 A g⁻¹, showing excellent cycling performance and rate capability.