While the past years have witnessed great achievement in pseudocapacitors, the inauguration of electrode materials of high-performance still remains a formidable challenge. Moreover, the capacity and rate capability of the electrode depends largely on its electrical conductivity, which ensures fast charge transfer kinetics in both the grain bulk and grain boundaries. Here, nickel hydroxides with oxygen vacancies are facilely fabricated via a hydrothermal method. The active materials exhibit a high specific capacitance of 3250 F·g⁻¹ and a high areal of capacitance of 14.98 F·cm⁻² at 4.6 mA·cm⁻². The asymmetric supercapacitor device based on our material delivers a high energy density of ∼ 71.6 Wh·kg⁻¹ and a power density of ∼ 17,300 W·kg⁻¹ and could retain ∼ 95% of their initial capacitance even after 30,000 cycles. In addition, the defect-rich hydroxides demonstrate higher electrical conductivity as well as dielectric constant, which is responsible for the superior pseudocapacitive performance. Our new scientific strategy in terms of taking the advantages of oxygen vacancies might open up new opportunities for qualified pseudocapacitive materials of overall high performances not only for nickel hydroxides but also for other metal hydroxides/oxides.

尽管过去几年赝电容器取得了巨大成就，但高性能电极材料的开创仍然是一个艰巨的挑战。此外，电极的容量和倍率性能在很大程度上取决于其电导率，这确保了晶粒体和晶界的快速电荷转移动力学。在这里，具有氧空位的氢氧化镍可以通过水热法轻松制备。该活性材料在4.6mA·cm ^{-2下表现出3250 F·g -1的高比电容和14.98 F·cm -2}的高面积电容。^{基于我们的材料的不对称超级电容器装置具有~ 71.6 Wh·kg -1}的高能量密度和~ 17,300 W·kg ^-1的功率密度，即使在30,000次循环后也能保留~ 95%的初始电容。此外，富含缺陷的氢氧化物表现出更高的电导率和介电常数，这也是其优越的赝电容性能的原因。我们利用氧空位优势的新科学策略可能会为整体高性能的合格赝电容材料开辟新的机会，不仅适用于氢氧化镍，也适用于其他金属氢氧化物/氧化物。