Significantly Enhanced Ultrathin NiCo-based MOF Nanosheet Electrodes Hybrided with Ti3C2Tx MXene for High Performance Asymmetric Supercapacitors
Yanzhong Wang, Yuexin Liu, Chao Wang, Hu Liu, Jiaoxia Zhang, Jing Lin, Jincheng Fan, Tao Ding, Jong Eun Ryu, Zhanhu Guo
Abstract
In situ synthesis of NiCo based metal-organic framework (MOF) nanosheets and the exfoliation of Ti 3 C 2 T x into isolated nanosheets (MXene), called, NiCo-MOF/Ti 3 C 2 T x hybrid nanosheets, are simultaneously achieved by a facile ultrasonic method. This method can effectively avoid the oxidation and restacking of Ti 3 C 2 T x nanosheets, and also make them uniformly disperse on the surface of NiCo-MOF. The formed NiCo-MOF/Ti 3 C 2 T x hybrid nanosheets achieve a high specific capacitance of 815.2 A g -1 at 1 A g -1 . The practical asymmetric supercapacitor (ASC) is fabricated using activated carbon and NiCo-MOF/Ti 3 C 2 T x hybrid nanosheets. The ASC device achieves an energy density of 39.5 Wh kg -1 at a power density of 562.5 W kg -1 , and also demonstrates a suitable cycling stability with 82.3 % of capacitance retention after 10000 continuous cycles at 5 Ag -1 . The enhanced electrochemical property of NiCo-MOF/Ti 3 C 2 T x is attributed to the nanosheet-like and mesoporous structure, high electronic conductivity, and synergistic effect of hybrid electroactive components.