Guo Ya-Fei, Luo Zhen-Hao, Zhang Nan, Wang Peng-Fei, Liu Zong-Lin, Lai Qin-Zhi, Shu Jie, Yi Ting-Feng
Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province, School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China.
School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
J Colloid Interface Sci. 2025 Jan;677(Pt A):459-469. doi: 10.1016/j.jcis.2024.07.250. Epub 2024 Jul 31.
High working voltage, large theoretical capacity and cheapness render MnO promising cathode candidate for aqueous zinc ion batteries (AZIBs). Unfortunately, poor electrochemical activity and bad structural stability lead to low capacity and unsatisfactory cycling performance. Herein, MnO material was fabricated through a facile precipitation reaction and divalent copper ions were introduced into the crystal framework, and ultra-small Cu-doped MnO nanocrystalline cathode materials with mixed valence states of Mn, Mn and Mn were obtained via post-calcination. The presence of Cu acts as structural stabilizer by partial substitution of Mn, as well as enhance the conductivity and reactivity of MnO. Significantly, based on electrochemical investigations and ex-situ XPS characterization, a synergistic effect between copper and manganese was revealed in the Cu-doped MnO, in which divalent Cu can catalyze the transformation of Mn and Mn to divalent Mn, accompanied by the translation of Cu to Cu and Cu. Benefitting from the above advantages, the MnO cathode doped with moderate copper (abbreviated as CMO-2) delivers large discharge capacity of 352.9 mAh g at 100 mA g, which is significantly better than MnO (only 247.8 mAh g). In addition, CMO-2 holds 203.3 mAh g discharge capacity after 1000 cycles at 1 A g with 98.6 % retention, and after 1000 cycles at 5 A g, it still performs decent discharge capacity of 104.2 mAh g. This work provides new ideas and approaches for constructing manganese-based AZIBs with long lifespan and high capacity.
高工作电压、大理论容量和低成本使MnO成为水系锌离子电池（AZIBs）中颇具潜力的阴极材料。不幸的是，其较差的电化学活性和结构稳定性导致容量较低且循环性能不尽人意。在此，通过简便的沉淀反应制备了MnO材料，并将二价铜离子引入晶体骨架，经过后续煅烧得到了具有Mn、Mn和Mn混合价态的超小Cu掺杂MnO纳米晶阴极材料。Cu的存在通过部分取代Mn起到结构稳定剂的作用，同时提高了MnO的导电性和反应活性。值得注意的是，基于电化学研究和非原位XPS表征，在Cu掺杂的MnO中揭示了铜和锰之间的协同效应，其中二价Cu可催化Mn和Mn向二价Mn的转变，同时伴随着Cu向Cu和Cu的转化。受益于上述优势，适度掺杂铜的MnO阴极（简称为CMO-2）在100 mA g时具有352.9 mAh g的大放电容量，明显优于MnO（仅247.8 mAh g）。此外，CMO-2在1 A g下循环1000次后仍保持203.3 mAh g的放电容量，保留率为98.6%，在5 A g下循环1000次后，仍具有104.2 mAh g的良好放电容量。这项工作为构建具有长寿命和高容量的锰基AZIBs提供了新的思路和方法。
