Diao Yuxin, Cao Haijie, Zhang Churui, Zhang Chuankun, Chen Hai-Chao
Institute of Materials for Energy and Environment, School of Materials Science and Engineering, Qingdao University, Qingdao, 266071, China.
Hubei Key Laboratory of Energy Storage and Power Battery, School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan, 442002, China.
ChemSusChem. 2025 Feb 1;18(3):e202401612. doi: 10.1002/cssc.202401612. Epub 2024 Nov 5.
Rechargeable nickel-zinc (Ni-Zn) batteries hold great promise for large-scale applications due to their relatively high voltage, cost-efficient zinc anode, and good safety. However, the commonly used cathode materials are susceptible to overcharging and experience irreversible capacity degradation, primarily as a result of low electrical conductivity and substantial limitations in volume-constrained proton diffusion. Here, we present a robust methodology for synthesizing hierarchical nickel-cobalt (Ni-Co) hydroxides characterized by hollow interiors and interconnected nanosheet shells with the help of in situ formed metal-organic frameworks (MOFs). The templating effect of the MOF induced the hierarchical structure, while the chemical etching of MOFs by Ni ions resulted in a hollow structure, thereby enhancing the surface area. Theoretical calculations suggested that incorporation of cobalt reduces the band gap, thereby improving electronic conductivity, and lowered the deprotonation energy, which mitigated overcharge issues. These advantages conferred improved specific capacity, rate capability, and cyclic stability to the Ni-Co hydroxide. The Ni-Zn cell delivered specific energy values of 338 Wh kg at 1.62 kW kg and 142 Wh kg at 29.89 kW kg. Our investigations undercoreed the critical role of MOFs as intermediates in the preparation of multi-component hydroxide and the construction of hiearchical structures to achieve superior performance.
可充电镍锌（Ni-Zn）电池因其相对较高的电压、成本效益高的锌负极和良好的安全性，在大规模应用方面具有巨大潜力。然而，常用的阴极材料容易过充，且会出现不可逆的容量衰减，这主要是由于其低电导率以及在体积受限的质子扩散方面存在重大限制。在此，我们借助原位形成的金属有机框架（MOF），提出了一种合成具有中空内部和相互连接的纳米片壳层结构的分级镍钴（Ni-Co）氢氧化物的稳健方法。MOF的模板效应诱导了分级结构的形成，而Ni离子对MOF的化学蚀刻导致了中空结构的产生，从而增加了表面积。理论计算表明，掺入钴会减小带隙，从而提高电子导电性，并降低去质子化能，进而缓解过充问题。这些优势赋予了Ni-Co氢氧化物更好的比容量、倍率性能和循环稳定性。该Ni-Zn电池在1.62 kW kg时的比能量值为338 Wh kg，在29.89 kW kg时为1四百四十二Wh kg。我们的研究强调了MOF作为中间体在制备多组分氢氧化物和构建分级结构以实现卓越性能方面的关键作用。
