Zhang Yingying, Dong Yutao, Wei Ruipeng, Guan Hui, Kang Xiyang, Al-Tahan Mohammed A, Zhang Jianmin
College of Chemistry, Zhengzhou University, Zhengzhou University, Zhengzhou 450001, China.
College of Science, Agricultural University, Henan, Zhengzhou 450002, China.
J Colloid Interface Sci. 2022 Feb;607(Pt 2):1153-1162. doi: 10.1016/j.jcis.2021.09.066. Epub 2021 Sep 14.
Transition metal oxalates have attracted wide attention due to the characteristics of the conversion reaction as anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), However, there are huge volume expansion and sluggish circulation dynamics during the reversible Li and Na insertion/extraction process, which would lead to unsatisfactory reversible capacity and stability. In order to solve these problems, a rod-like structure NiCoCO·2HO is in-situ formed on the reduced graphene oxide layer (NiCoCO·2HO/rGO) in a glycol-water mixture medium via an interface induced engineering strategy. Benefitting from the synergistic cooperation of nano-diameter rod-like structure and high conductive rGO networks, the experimental results show that the prepared NiCoCO·2HO/rGO electrode has predominant rate performance and ultra-long cycle stability. For the LIBs, it not only exhibits an ultrahigh reversible capacity (1179.9 mA h g at 0.5 A g after 300 cycles), but also presents outstanding rate and cycling performance (646.5 mA h g at 5 A g after 1200 cycles). Besides, the NiCoCO·2HO/rGO electrode displays remarkable sodium storage capacity of 221.6 mA h g after 100 cycles at 0.5 A g. Further, the extraordinary electrochemical capability of NiCoCO·2HO/rGO active material is also reflected in two full-cells, assembled using commercial LiCoO as cathode for LIBs and commercial NaV(PO) as cathode for SIBs, both of which can show wonderful specific capacity and cycling stability. It is found in in-situ Raman experiments that the reversible changes of oxalate peaks are monitored in a charge/discharge process, which is scientific evidence for the transform reaction mechanism of metal oxalates in LIBs. These findings not only provide important ideas for studying the charge/discharge storage mechanism but also give scientific basis for the design of high-performance electrode materials.
过渡金属草酸盐因其作为锂离子电池（LIBs）和钠离子电池（SIBs）阳极材料的转换反应特性而备受关注。然而，在可逆的锂和钠嵌入/脱出过程中存在巨大的体积膨胀和缓慢的循环动力学，这将导致可逆容量和稳定性不尽人意。为了解决这些问题，通过界面诱导工程策略，在乙二醇 - 水混合介质中的还原氧化石墨烯层上原位形成了棒状结构的NiCoCO·2HO（NiCoCO·2HO/rGO）。受益于纳米直径棒状结构与高导电性rGO网络的协同合作，实验结果表明，制备的NiCoCO·2HO/rGO电极具有优异的倍率性能和超长的循环稳定性。对于LIBs，它不仅在300次循环后于0.5 A g下表现出超高的可逆容量（1179.9 mA h g），而且还呈现出出色的倍率和循环性能（在5 A g下1200次循环后为646.5 mA h g）。此外，NiCoCO·2HO/rGO电极在0.5 A g下100次循环后显示出221.6 mA h g的显著储钠容量。此外，NiCoCO·2HO/rGO活性材料的非凡电化学性能还体现在两个全电池中，分别使用商业LiCoO作为LIBs的阴极和商业NaV(PO)作为SIBs的阴极组装而成，两者均能表现出出色的比容量和循环稳定性。在原位拉曼实验中发现，在充放电过程中监测到草酸盐峰的可逆变化，这是LIBs中金属草酸盐转化反应机理的科学证据。这些发现不仅为研究充放电存储机制提供了重要思路，也为高性能电极材料的设计提供了科学依据。
