A Novel VW₁₂ POMCPs with - Stacking and Honeycomb 2D Network Structure Accommodated by MXenes as High-Performance Supercapacitors Negative Electrode

The key to obtain supercapacitors with high energy density is rational design and synthesis of negative electrode materials. Herein, a new type of polyoxometalate-based coordination polymer was prepared by one-step hydrothermal method. Polymer 1 with honeycomb two-dimensional network structure is beneficial to improve electrical conductivity and storage capacity because of its pi-pi stacking interaction. Ti3C2Tx, an MXene material with excellent electrical conductivity, was mixed with compound 1, which has rich redox reactions. As expected, 1@Ti3C2Tx exhibited outstanding specific capacitance (768.7 F g(-1) at 8 A g(-1)), which is superior to many materials. In addition, the hybrid material also showed good cycle stability (88.1 % capacity retention after 1000 cycles). This work provides an effective way to develop hybrid electrode materials based on polyoxometalate-based coordination polymers as supercapacitors. In addition, using 1@Ti3C2Tx as the negative electrode material and celery leaf carbon paper as the positive electrode material, the asymmetric supercapacitor device is fabricated. When the power density is 629.7 W kg(-1), the energy density is 9.2 Wh kg(-1), which indicates that it has a good application prospect.