Based on the redox couple reaction of Mn³⁺/Mn⁴⁺, the theoretical capacitance of manganese dioxide (MnO₂) has a very high value of 1370 F/g but the specific capacitance of MnO₂ in the reported literature is still under 300 F/g. The potential window of MnO₂ in the previously published studies is approximately 1 V which, considering E = ½CV², limits the power and energy densities far below the theoretical value. In this work, we developed an ultra-thin K⁺ doped δ-MnO₂ nanosheets array electrode the potential window of which extended to 0-1.2 V with a highly reversible capacitance of 366 F/g. When the potential window reaches 1.2 V, the fast-redox reaction of MnO₂ and the K⁺ intercalation/deintercalation process restrains water decomposition in kinetics. A high potency aqueous asymmetric supercapacitor (K-MnO₂//AC) was drafted with K-MnO₂ as a positive electrode which exhibited a stable working potential window of 0-2.2 V in 1 M Na₂SO₄ aqueous electrolyte. This device has demonstrated an excellent energy density of 56 Wh/kg at a power density of 550 W/kg and an ultralong cycle performance with capacitance retention of 98% over 10000 cycles at the current density of 10 A/g. This approach leads to new prospects for emerging high workable potential window aqueous energy storage devices.

基于Mn ³⁺ / Mn ⁴⁺的氧化还原偶联反应，二氧化锰（MnO ₂）的理论电容值非常高，为1370 F / g，但所报道的文献中MnO ₂的比电容仍在300以下氟/克 的MnO的电位窗口₂在先前公布的研究是约1 V其中，考虑到E =½CV ²，限制远低于理论值的功率和能量密度。在这项工作中，我们开发了一种超薄ķ ⁺ δ掺杂的MnO ₂纳米片阵列电极，其电位窗口扩展至0-1.2 V，具有366 F / g的高度可逆电容。当电势窗口达到1.2 V时，MnO ₂的快速氧化还原反应和K ⁺嵌入/去嵌入过程抑制了水的动力学分解。以K-MnO ₂为正极绘制了高效的水不对称超级电容器（K-MnO ₂ // AC），该溶液在1 M Na ₂ SO _4中显示0-2.2 V的稳定工作电位窗口水性电解质。该器件在550 W / kg的功率密度下具有出色的56 Wh / kg的能量密度，在10 A / g的电流密度下，在10000次循环中具有98％的电容保持率，超长循环性能。这种方法为新兴的高可行的潜在窗口含水储能设备带来了新的前景。