Wu Bing, Liu Jiaxing, Rao Shengpu, Zheng Chengjin, Song Weihao, Ma Qing, Niu Jin, Wang Feng
State Key Laboratory of Chemical Resource Engineering, Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Small. 2024 Aug;20(31):e2400926. doi: 10.1002/smll.202400926. Epub 2024 Mar 12.
As corrosion products of Zn anodes in ZnSO electrolytes, ZnSO (OH)·xHO with loose structure cannot suppress persistent side reactions but can increase the electrode polarization and induce dendrite growth, hindering the practical applications of Zn metal batteries. In this work, a functional layer is built on the Zn anode by a gelatin-assistant corrosion and low-temperature pyrolysis method. With the assistant of gelatin, undesired corrosion products are converted into a uniform nanoflake array comprising ZnO coated by gelatin-derived carbon on Zn foil (denoted Zn@ZnO@GC). It is revealed that the gelatin-derived carbons not only enhance the electron conductivity, facilitate Zn desolvation, and boost transport/deposition kinetics, but also inhibit the occurrence of hydrogen evolution and corrosion reactions on the zincophilic Zn@ZnO@GC anode. Moreover, the 3D nanoflake array effectively homogenizes the current density and Zn concentration, thus inhibiting the formation of dendrites. The symmetric cells using the Zn@ZnO@GC anodes exhibit superior cycling performance (over 7000 h at 1 mA cm/1 mAh cm) and without short-circuiting even up to 25 mAh cm. The Zn@ZnO@GC||NaVO full cell works stably for 5000 cycles even with a limited N/P ratio of ≈5.5, showing good application prospects.
作为锌阳极在硫酸锌电解液中的腐蚀产物，结构疏松的碱式硫酸锌（ZnSO(OH)·xH₂O）无法抑制持续的副反应，反而会增加电极极化并诱导枝晶生长，阻碍了锌金属电池的实际应用。在这项工作中，通过明胶辅助腐蚀和低温热解方法在锌阳极上构建了一个功能层。在明胶的辅助下，不需要的腐蚀产物转化为在锌箔上由明胶衍生碳包覆氧化锌组成的均匀纳米片状阵列（表示为Zn@ZnO@GC）。研究表明，明胶衍生碳不仅提高了电子导电性，促进了锌的去溶剂化，并加快了传输/沉积动力学，而且还抑制了亲锌的Zn@ZnO@GC阳极上析氢和腐蚀反应的发生。此外，三维纳米片状阵列有效地使电流密度和锌浓度均匀化，从而抑制了枝晶的形成。使用Zn@ZnO@GC阳极的对称电池表现出优异的循环性能（在1 mA cm⁻²/1 mAh cm⁻²下超过7000小时），甚至在高达25 mAh cm⁻²时也不会短路。即使在有限的N/P比约为5.5的情况下，Zn@ZnO@GC||NaVO₃全电池仍能稳定工作5000次循环，显示出良好的应用前景。
