Interface design based on Ti3C2 MXene atomic layers of advanced battery-type material for supercapacitors

Interfacial engineering provides efficient methods to enhance conductivity and structural stability of active electrode materials. Herein, 1-3 atomic layered Ti3C2 MXene is introduced to strengthen flexible Ni2Co-LDHs nanoarrays, forming the 3D irregular honeycomb-like sandwich-type composite. Strong interfacial interactions and excellent conductivity of AL-Ti3C2 MXene give the composite ultrahigh rate capability and long-life stability in battery-type supercapacitors. The rate capability reaches 126 mAh g(-1) at 150 A g(-1), similar to 5.7 times of pure Ni2Co-LDHs (22 mAh g(-1)), which can be up to 92 mAh g(-1) even at 300 A g(-1). It also gives outstanding stability of similar to 90% capacity retention after 10000 cycles (vs. similar to 17% for Ni2Co-LDHs). The introduced Ti3C2 MXene atomic layers much enhances the intrinsic performance of NiCo-LDHs. Density functional theory (DFT) calculation reveals 1.07 electrons transfer per unit cell from LDHs to AL-Ti3C2 MXene at the very stable interfaces with ultralow energy of -13.48 eV. The interfaces much improve conductivity and reaction kinetics of outer LDHs. The fabricated interfaces also decrease surficial hydrogen adsorption energy from 1.67 to 1.47 eV, benefiting for electrochemical performance. This work provides a feasible route to develop excellent battery-type electrode materials of supercapacitor via interfacial design.