Anchoring MnO₂ on nitrogen-doped porous carbon nanosheets as flexible arrays cathodes for advanced rechargeable Zn–MnO₂ batteries

Controllable construction of advanced Mn-based cathodes is of great importance for the development of flexible rechargeable Zn-MnO₂ batteries. Herein we report an effective flexible composite strategy to construct integrated arrays cathodes by rationally anchoring active MnO₂ on novel N-doped porous carbon nanosheets (N-CNSs) arrays grown on carbon cloth. Typically, hydrothermal-synthesized MnO₂ nanoflakes are strongly anchored on the conductive N-CNSs skeleton forming flexible N-CNSs@MnO₂ core/shell arrays. Interestingly, active Zn anode is also compatible with N-CNSs skeleton forming flexible integrated anode. Positive effects are demonstrated in the above N-CNSs@MnO₂ core/shell arrays including good flexibility, high electrical conductivity, large porosity & specific surface area, and strong mechanical stability. Accordingly, the Zn ion storage kinetics is optimized in the obtained N-CNSs@MnO₂ cathodes, which can deliver a high capacity of 303.7 ​mAh g⁻¹ ​at 0.2 ​A ​g⁻¹ and superior long-term lifespan (91.6% retention after 1800 cycles at 2 ​A ​g⁻¹) in aqueous electrolyte. More importantly, the as-assembled flexible quasi-solid-state N-CNSs@MnO₂//N-CNSs@Zn battery can exhibit a high energy density of 150.6 ​Wh kg⁻¹ with a power density of 7.9 ​kW ​kg⁻¹. Our work shows a novel carbon-based flexible design for construction of high-performance Zn-MnO₂ devices.