N, P dual-doped MXene nanocomposites for boosting zinc-ion storage capability

Ti3C2 MXene offers a new option for obtaining high performance zinc ion hybrid capacitors due to its good electronic conductivity, chemical stability, low cost and environmental friendliness. Therefore, we prepared Ti3C2 MXene (Ti3C2N,P) dual-doped with nitrogen and phosphorus by hydrothermal method using Ti3C2 as raw material. The doping of heteroatoms into MXene forms more vacancies and defects, which provide more active adsorption sites for electrochemical reactions, thus improving the energy storage performance of zinc-ion hybrid capacitors. Zinc-ion hybrid supercapacitors (ZIHCs) combining Ti3C2N,P cathodes and zinc metal anodes were found to exhibit outstanding energy storage properties due to the synergistic effect of Ti3C2's superior electronic conductivity. The capacitor has a high specific capacitance of 238.95 F g − 1 and a high energy density of 43.89 Wh kg−1 at a current density of 0.5 A g − 1 much higher than the 62.68 F g − 1 and 11.51 Wh kg−1 of undoped MXene. In addition, the supercapacitor has good cycling stability, exhibiting 97.8% capacity retention after 10,000 cycles. This research shows that the design and modification of MXene materials by doping with nitrogen and phosphorus atoms can significantly improve the energy storage properties of MXene-based supercapacitors.