Polyoxometalate-Incorporated Host-Guest Framework Derived Layered Double Hydroxide Composites for High-Performance Hybrid Supercapacitor^†

Metal organic frameworks have been employed as high-performance layered double hydroxide (LDH) composite supercapacitor electrode materials but have shown unsatisfactory redox ability and stability. Herein, a host-guest CuMo-based polyoxometalate-based metal organic framework (POMOF) with copious electrochemically active sites and strong electrochemical redox activities has been effectively coupled with POM-incorporated CoNi-LDH to develop a nanocomposite (NENU-5@CoNi-LDH) by a simple solvothermal method. The designed electrode shows a high specific capacity of 333.61 mAh·g^–1 at 1 A·g^–1. In addition, the novel hybrid symmetric supercapacitor NENU-5@CoNi-LDH/active carbon (AC) demonstrated a high energy density of 80.8 Wh·kg^–1 at a power density of 750.7 W·kg^–1. Interestingly, the nanocomposite of NENU-5@CoNi-LDH exhibits an outstanding capacitance retention of 79% after 5000 charge-discharge cycles at 10 A·g^–1. This work provides a new strategy and will be the backbone for future energy storage research.