Ultrahigh-Power Pseudocapacitors Based on Ordered Porous Heterostructures of Electron-Correlated Oxides

Nanostructured transition-metal oxides can store high-density energy in fast surface redox reactions, but their poor conductivity causes remarkable reductions in the energy storage of most pseudocapacitors at high power delivery (fast charge/discharge rates). Here it is shown that electron-correlated oxide hybrid electrodes made of nanocrystalline vanadium sesquioxide and manganese dioxide with 3D and bicontinuous nanoporous architecture (NP V₂O₃/MnO₂) have enhanced conductivity because of metallization of electron-correlated V₂O₃ skeleton via insulator-to-metal transition. The conductive V₂O₃ skeleton at ambient temperature enables fast electron and ion transports in the entire electrode and facilitates charge transfer at abundant V₂O₃/MnO₂ interface. These merits significantly improve the pseudocapacitive behavior and rate capability of the constituent MnO₂. Symmetric pseudocapacitors assembled with binder-free NP V₂O₃/MnO₂ electrodes deliver ultrahigh electrical powers (up to ≈422 W cm²³) while maintaining the high volumetric energy of thin-film lithium battery with excellent stability.