以KMnO₄、MnSO₄·H₂O、（NH₄）₂S₂O₈和盐酸为原料，通过控制水热反应的温度和时间合成不同晶型的二氧化锰（MnO₂）。通过XRD、SEM、TEM技术对材料的结构和形貌进行表征。结果表明，所合成的MnO₂均为纳米颗粒，但不同晶型的MnO₂呈现出不同的微观形貌。对比其电化学性能发现：δ-MnO₂由于其独特的花球结构提供大量的反应位点，性能明显优于其他晶型的MnO₂，在2 A/g的电流密度下循环1400周次可以达到623.48 mAh/g的比容量。采用循环伏安法、电化学阻抗和恒电流间歇滴定技术探究MnO₂电极的动力学特性，δ-MnO₂拥有更高的Li⁺扩散速率。

Different crystal forms of manganese dioxide （MnO₂） are synthesized using KMnO₄， MnSO₄·H₂O， （NH4）₂S₂O₈， and hydrochloric acid as raw materials by precisely controlling the temperature and duration of a hydrothermal reaction. The structure and morphology of the materials are characterized using XRD， SEM， and TEM. The results show that the synthesized MnO₂ nanoparticles display different microscopic morphologies depending on their crystal forms. A comparison of their electrochemical performances indicates that δ-MnO₂， due to its unique flower-like structure， provides many reaction sites， leading to superior performance compared to other crystal forms of manganese dioxide. At a current density of 2 A/g， δ-MnO₂ achieves a capacity of 623.48 mAh/g after 1400 cycles. The kinetic properties of the MnO₂ electrode are investigated using cyclic voltammetry， electrochemical impedance spectroscopy， and constant current intermittent titration techniques. It reveals that δ-MnO₂ exhibits a higher Li⁺ diffusion rate.