KOH-assisted aqueous synthesis of ZIF-67 with high-yield and its derived cobalt selenide/carbon composites for high-performance Li-ion batteries

To solve the environmental pollution and low yield during the sythesis of zeolitic imidazolate frameworks (ZIFs) and their derived materials, a KOH-assisted aqueous strategy is proposed to synthesize cobalt zeolitic imidazolate framework (ZIF-67) polyhedrons, which are used as precursors to prepare cobalt selenide/carbon composites with different crystal phases (Co0.85Se, CoSe2). When evaluated as anode material for lithium ion batteries, Co0.85Se/C composites deliver a reversible capacity of 758.7 m A.h.g(-1) with a capacity retention rate of 90.5% at 1.0 A.g(-1) after 500 cycles, and the superior rate capability is 620 mA.h.g(-1) at 2.0 A.g(-1). The addition of KOH accelerates the production of ZIF-67 crystals by boosting deprotonation of dimethylimidazole, resulting in rapid growth and structures transition from two-dimensional to three-dimensional of ZIF-67 in aqueous solution, which greatly promotes the application of MOFs in the field of energy storage and conversion. (C) 2022 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

A KOH-assisted aqueous strategy is proposed to synthesize ZIF-67 polyhedrons, which are used as precursors to prepare cobalt selenide/carbon composites with different crystal phases. The composites show high reversible capacity and rate capability when evaluated as anode material for lithium ion batteries.