Study on Electrodeposition of Co-Ni Double Hydroxides and Its Supercapacitor Performance

超级电容器具有快速充放电、高循环稳定性等特点，在航空航天、交通运输等领域中得到广泛应用。过渡金属钴、镍元素拥有多重价态，其化合物具有多反应活性位点，是极具潜力的超级电容器电极材料。然而，该材料在充放电过程中易出现结构坍塌、活性物质脱落的现象，导致其循环稳定性和倍率性能不理想。本文利用循环伏安技术进行了钴镍双金属氢氧化物的电化学沉积，研究了沉积液中Co2+和Ni2+的比例及沉积圈数对材料电化学表现的影响。研究结果证明，在Co2+和Ni2+浓度达到2:1的条件下，电极材料在1 mA/cm2下的面积比电容为444.0 mF/cm2，在20 mA/cm2下可维持70.1%的面积比电容值。电极材料的负载量随着沉积圈数的增加而增加，在高负载量(4.5 mg/cm2)下，电极的倍率性能仍十分优异。Supercapacitors, characterized by their fast charge/discharge rates and high cycle stability, have found extensive applications in aerospace, transportation, and other fields. Transition metals cobalt and nickel, with their multiple oxidation states, demonstrate compounds containing abundant active sites, making them highly promising electrode materials for supercapacitors. However, these materials often suffer from structural collapse and active material detachment during charge/discharge processes, leading to suboptimal cycling stability and rate performance. This study employed cyclic voltammetry for electrodeposition of cobalt-nickel bimetallic hydroxides, systematically investigating the effects of Co2+/Ni2+ ratio in the deposition solution and the number of deposition cycles on the electrochemical performance. The results revealed that electrodes prepared with a Co2+/Ni2+ ratio of 2:1 exhibited an impressive area-specific capacitance of 444.0 mF/cm2 at 1 mA/cm2, while maintaining 70.1% area-specific capacitance retention at 20 mA/cm2. The electrode material loading increased proportionally with deposition cycles, and notably, even at high mass loading (4.5 mg/cm2), the electrodes maintained excellent rate performance.