Metal-organic frameworks derived low-crystalline NiCo_(2)S_(4)/Co_(3)S_(4) nanocages with dual heterogeneous interfaces for high-performance supercapacitors

摘要

Nickel cobalt bimetallic heterogeneous sulfides are attractive battery-type materials for electrochemical energy storage.However,the precise synthesis of electrode materials that integrate highly efficient ions/electrons diffusion with abundant charge transfer channels has always been challenging.Herein,an effective and concise controllable hydrothermal approach is reported for tuning the crystalline and integrated structures of MOF-derived bimetallic sulfides to accelerate the charge transfer kinetics,and thus enabling rich Faradaic redox reaction.The as-obtained low-crystalline heterogeneous NiCo_(2)S_(4)/Co_(3)S_(4)nanocages exhibit a high specific capacity(1023 C/g at 1 A/g),remarkable rate performance(560 C/g at 10A/g),and outstanding cycling stability(89.6%retention after 5000 cycles).Furthermore,hybrid supercapacitors fabricated with NiCo_(2)S_(4)/Co_(3)S_(4)and nitrogen-doped reduced graphene oxide display an outstanding energy density of 40.8 Wh/kg at a power density of 806.3 W/kg,with an excellent capacity retention of 88.3%after 10000 charge-discharge cycles.