Carbon-based materials, such as carbon nanotubes, graphene and mesoporous carbons, are typical electrochemical double-layer capacitive electrodes of supercapacitors (SCs). Although these carbon electrode materials have excellent electrochemical stability, they usually have a low capacitance. Therefore, pseudocapacitive materials are often combined with them to increase the capacitance. Among these pseudocapacitive materials, manganese dioxide (MnO₂) has been widely used because of its high theoretical specific capacitance, low-cost, abundance, and environmentally friendly nature. However, the use of MnO₂ often produces rather low actual specific capacitances due to its poor electrical conductivity, serious phase transformation and large volumetric changes during repeated charge and discharge. To explore high-performance MnO₂/carbon composite electrode materials, it is necessary to understand the charge storage mechanisms of MnO₂. These are analyzed and classified into four types: surface chemisorption of cations, intercalation-deintercalation of cations, a tunnel storage mechanism and a charge compensation mechanism. Although the fourth involves pre-interaction of the cations in MnO₂, the essence of all these mechanisms is the valence transition of manganese atoms between +3 and +4, and many mechanisms are usually involved in MnO₂-based SCs because of the complicated charge storage process. Critical challenges and possible strategies for achieving high-performance MnO₂/carbon-based SCs are discussed and prospective solutions are presented.

碳基材料，如碳纳米管、石墨烯和介孔碳，是典型的超级电容器（SCs）电化学双层电容电极。尽管这些碳电极材料具有优异的电化学稳定性，但它们通常具有较低的电容。因此，常将赝电容材料与它们结合以增加电容。在这些赝电容材料中，二氧化锰（MnO ₂）因其理论比电容高、成本低、资源丰富和环境友好等优点而被广泛应用。然而，使用 MnO ₂由于其导电性差，相变严重，重复充放电过程中体积变化大，因此通常会产生相当低的实际比电容。为了探索高性能MnO ₂ /碳复合电极材料，有必要了解MnO ₂的电荷存储机制。这些被分析并分为四种类型：阳离子的表面化学吸附、阳离子的嵌入-脱嵌、隧道存储机制和电荷补偿机制。虽然第四个涉及 MnO _{2 中}阳离子的预相互作用，但所有这些机制的本质是锰原子在 +3 和 +4 之间的价态跃迁，通常许多机制都涉及 MnO ₂基于复杂的电荷存储过程的 SC。讨论了实现高性能 MnO ₂ /碳基 SCs 的关键挑战和可能的策略，并提出了前瞻性的解决方案。