Facile synthesis of transition metal complexes wrapped Ti3C2Tx by a PVP-assisted liquid impregnation strategy with enhanced electrochemical performance for supercapacitors

Abstract

The development of Ti3C2Tx-based high performance electrode materials has been proposed to meet the practical requirements of supercapacitors. In this study, transition metal complexes decorated MXene Ti3C2Tx hybrid electrode nanocomposites are fabricated by a facile polyvinylpyrrolidone (PVP)-assisted liquid impregnation strategy (abbreviated as PVP-M/akTi3C2Tx (M = Mn or Ni)). The intercalated Ti3C2Tx is observed to possess a distinct layered structure wrapped by cloud-like Mn/Ni complexes, which form a heterojunction to help the charge transfer of PVP-M/akTi3C2Tx in aqueous electrolytes such as KOH, LiOH, Li2SO4 and Na2SO4. The electrochemical performance of pristine and modified MXene in the above electrolytes changes greatly, mainly due to the difference of electrolytes’ ionic radius and conductivity. Typically, the PVP-Mn/akTi3C2Tx and PVP-Ni/akTi3C2Tx nanocomposites exhibit superior specific capacitances of 154.6 F g−1 and 167.65 F g−1 at 0.3 A g−1 current density in 1 M KOH electrolyte, respectively. Moreover, due to the complete progressive activation process of the electrode materials, the specific capacitance further increased by 25% and 56% after thousands of cycles, and finally kept at 95.70% and 96.21% of the maximum value respectively, indicating the superstability of these electrode materials. This study provides a new perspective to tailor the microstructures of Ti3C2Tx electrode materials for energy applications.