Nanoscale Parallel Circuitry Based on Interpenetrating Conductive Assembly for Flexible and High‐Power Zinc Ion Battery

Abstract High‐rate capability has become an important feature for energy storage devices, but it is often accompanied with a significant reduction in energy density. Therefore, developing an energy storage technology that combines high‐rate capability with high energy density is a great challenge for next‐generation electronic devices. Here, parallel circuitry is constructed at the nanoscale to lower the resistance for ion and electron transport that largely determines the rate performance. The parallel circuitry is constructed through intertwining continuous carbon nanotubes with an interpenetrating conductive assembly based on hierarchically layered MXene (Ti 3 C 2 T x ) functionalized by KMnO 4 (MnO x @Ti 3 C 2 T x ). The assembly shows ultrafast rate capability, e.g., maintaining 50% capacity when the current density increases from 0.1 to 10 A g −1 . Investigations of the kinetics and charge storage mechanisms confirm the efficiency of the designed parallel circuitry in improving rate capability by providing rapid pathways for ions and electrons, as well as dividing the current flow evenly into individual MnO x @Ti 3 C 2 T x flakes in the assembly. The flexible MnO x @Ti 3 C 2 T x based electrode endows zinc ion batteries with outstanding mechanical robustness and good power delivering performance. The paradigm presented here paves a new way for designing electrodes with high‐rate capability toward next‐generation energy storage technologies.