Significantly Enhanced Ultrathin NiCo-based MOF Nanosheet Electrodes Hybrided with Ti3C2Tx MXene for High Performance Asymmetric Supercapacitor

Yanzhong Wang1,2,Email

Yuexin Liu1

Chao Wang1,2,Email

Hu Liu3,4

Jiaoxia Zhang3,7

Jing Lin3

Jincheng Fan5

Tao Ding6

Jong E. Ryu8

Zhanhu Guo3,Email

1 School of Materials Science and Engineering, North University of China, Taiyuan, 030051, China

2 Advanced energy materials and system institute, North University of China, Taiyuan, 030051, China

3 Integrated Composites Laboratory (ICL), Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN, 37966, USA

4 Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education, National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou, 450001, China

5 College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha, 410114, China

6 College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China

7 School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China

8 Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA

Abstract

In situ synthesis of NiCo based metal-organic framework (MOF) nanosheets and the exfoliation of Ti3C2Tx into isolated nanosheets (MXene), called, NiCo-MOF/Ti3C2Tx hybrid nanosheets, are simultaneously achieved by a facile ultrasonic method. This method can effectively avoid the oxidation and restacking of Ti3C2Tx nanosheets, and also make them uniformly disperse on the surface of NiCo-MOF. The formed NiCo-MOF/Ti3C2Tx 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/Ti3C2Tx 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 A g-1. The enhanced electrochemical property of NiCo-MOF/Ti3C2Tx is attributed to the nanosheet-like and mesoporous structure, high electronic conductivity, and synergistic effect of hybrid electroactive components.