High-rate and long-life flexible aqueous rechargeable zinc-ion battery enabled by hierarchical core shell heterostructures

Aqueous rechargeable zinc-ion batteries (ZIBs) are potential alternative candidates for current commercial lithium-ion batteries due to their cost-efficiency, safety and sustainable nature. As one of the prominent cathode materials, MnO2 exhibits high operating voltage and theoretical capacity. Yet, its poor electrochemical kinetics, low conductivity, and lifespan prevent its further application. Herein, an effective strategy for the construction of hierarchical TiN@MnO2 nanowire arrays (NWAs) core-shell heterostructures directly grown on carbon cloth (CC) is demonstrated to systematically solve the above issues. First-principles calculations reveal that decreased bandgap and Zn2+ diffusion barrier as well as more stable structure of the host material after Zn2+ insertion promote the electrochemical kinetics of TiN@MnO2. As a result, TiN@MnO2 NWAs/CC exhibits significantly increased capacity (385.1 vs. 310 and 194 mA h g?1 at 0.1 A g?1), rate performance (127.6 mA h g?1 vs. 49.7 and 37.4 mA h g?1 at 4.0 A g?1) and cycling stability (101.6% capacity retention over 2300 cycles vs. 14.0% and 11.9%) compared with TiO2@MnO2 NWAs/CC and MnO2 NSs/CC, respectively. Finally, the as-Assembled flexible ZIBs with TiN@MnO2 NWAs/CC cathode deliver an ultrahigh energy density of 327.7 W h kg?1 at 135.6 W kg?1. The proposition of the core-shell idea provides a novel strategy for development ZIBs.