Peanut Shell-Derived Carbon Microsheet@MnO₂ Nanoparticles Composite for Ultra Long-Cycling Aqueous Zinc-Ion Batteries

High-performance and low-cost cathode materials originating from renewable resources are crucial factors in the practical application of Zn-ion batteries (ZIBs). In this work, a peanut shell carbon (PSC) microsheet was prepared from renewable and low-cost agricultural waste by a high-temperature carbonization method. Then, MnO₂ nanoparticles were in situ grown on PSC microsheets by a simple hydrothermal method to obtain a PSC@MnO₂ composite material. The unique micro-nano structure plays a vital role in the synergistic effect between the excellent electrical conductivity of the PSC matrix and the high specific capacity of MnO₂ nanoparticles, which facilitates electron/ion transport in the entire electrode and enables the composite to have excellent electrochemical properties. The PSC@MnO₂ composite can achieve a high reversible capacity of 645.5 mA h g^-1 at the current density of 50 mA g^-1, and the specific reversible capacity of the PSC@MnO₂ composite is still maintain 329.4 mA h g^-1 at 100 mA g^-1 after 400 cycles, which is much higher than PSC material (2 mA h g^-1) and commercial MnO₂(MnO₂) (112 mA h g^-1). Remarkably, the PSC@MnO₂ remained a reversible capacity of 128.3 mA h g^-1 after 3000 cycles at 500 mA g^-1, and the capacity retention of PSC@MnO₂ was 87.1%. This work opens up possibilities for the application of biomass carbon and MnO₂ composites and promotes low-cost, renewable, green eco-friendly, and high-performance aqueous rechargeable ZIBs.