School of Materials Science and Engineering, Chang'an University, Xi'an, 710061, China.
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
Small. 2023 Feb;19(8):e2206287. doi: 10.1002/smll.202206287. Epub 2022 Dec 11.
The α-Ni(OH) is regarded as one promising cathode for aqueous nickel-zinc batteries due to its high theoretical capacity of ≈480 mAh g , its practical deployment however suffers from the poor stability in strong alkaline solution, intrinsic low electrical conductivity as well as the retarded ionic diffusion. Herein, a 3D (three dimensional) macroporous α-Ni(OH) nanosheets with Co doping is designed through a facile and easily scalable electroless plating combined with electrodeposition strategy. The unique micrometer-sized 3D pores come from Ni substrate and rich voids between Co-doping α-Ni(OH) nanosheets can synergistically afford facile, interconnected ionic diffusion channels, sufficient free space for accommodating its volume changes during cycling; meanwhile, the Co-doping can stabilize the structural robustness of the α-Ni(OH) in the alkaline electrolyte during cycling. Thus, the 3D α-Ni(OH) shows a high capacity of 284 mAh g at 0.5 mA cm with an excellent retention of 78% even at 15 mA cm , and more than 2000 stable cycles at 6 mA cm , as well as the robust cycling upon various flexible batteries. This work provides a simple and efficient pathway to enhance the electrochemical performance of Ni-Zn batteries through improving ionic transport kinetics and stabilizing crystal structure of cathodes.
α-Ni(OH) 由于其高达 ≈480 mAh g 的理论比容量，被认为是一种很有前途的水系镍锌电池正极材料。然而，其实际应用受到强堿性溶液中稳定性差、本征电导率低以及离子扩散缓慢的限制。在此，通过一种简便且易于扩展的化学镀与电沉积相结合的策略，设计了一种具有 Co 掺杂的 3D（三维）大孔α-Ni(OH)纳米片。独特的微米级 3D 孔来自 Ni 基底，而 Co 掺杂α-Ni(OH)纳米片之间的丰富空隙可以协同提供易于连通的离子扩散通道，为其在循环过程中的体积变化提供充足的自由空间；同时，Co 掺杂可以在碱性电解液中稳定α-Ni(OH)的结构完整性。因此，3Dα-Ni(OH)在 0.5 mA cm 时具有 284 mAh g 的高容量，在 15 mA cm 时保持了 78%的优异倍率性能，在 6 mA cm 时超过 2000 次稳定循环，以及在各种柔性电池中的稳健循环。这项工作通过提高离子传输动力学和稳定正极的晶体结构，为提高镍锌电池的电化学性能提供了一种简单而有效的途径。
