One-pot synthesis of 2D Ti3C2/Ni2CO3(OH)2 composite as electrode material with superior capacity and high stability for hybrid supercapacitor.

Abstract MXene-based materials are promising electrode materials for supercapacitors. Herein, Ni 2 CO 3 (OH) 2 nanosheets and/or nanoparticles are in-situ grown on the surface of two-dimensional (2D) Ti 3 C 2 to form Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composites during one-pot hydrothermal processing. The uniform distribution of Ni 2 CO 3 (OH) 2 on Ti 3 C 2 is due to the electrostatic interaction between positively charged nickel ions and negatively charged Ti 3 C 2. Importantly, the electrochemical performance of Ti 3 C 2 /Ni 2 CO 3 (OH) 2 are enhanced. The 30-Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite electrode exhibits a specific capacity of 173.8 mAh g−1 at 1 A g−1 and excellent cycling stability (capacity retention of 80.1% after 5000 cycles at 10 A g−1). The hybrid supercapacitor using 30-Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite as positive electrode and active carbon as negative electrode delivers a high energy density of 28.2 Wh kg−1 at a power density of 374.8 W kg−1. The super performance of the composite electrode is attributed to the synergistic effects of good redox activity of Ni 2 CO 3 (OH) 2 particles combined with high electronic conductivity of 2D Ti 3 C 2. The excellent electrochemical performance of Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite indicates its potential as a promising electrode material to high energy/power density energy storage devices. Graphical abstract Image 1 Highlights • One-pot in-situ synthesis of Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite is explored. • Synergistic effects of Ni 2 CO 3 (OH) 2 and Ti 3 C 2 enhance the electrochemical performance of composite. • The structure and property of Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite can be simply controlled by Ti 3 C 2 content. • The 30-Ti 3 C 2 /Ni 2 CO 3 (OH) 2 composite exhibits high specific capacity (173.8 mAh g−1 at 1 A g−1) and good cycling stability. • The 30-Ti 3 C 2 /Ni 2 CO 3 (OH) 2 //AC hybrid supercapacitor exhibits high energy density of 28.2 Wh kg−1 at a power density of 374.8 W kg−1. [ABSTRACT FROM AUTHOR]