Clarisza Adriana, Bezabh Hailemariam Kassa, Jiang Shi-Kai, Huang Chen-Jui, Olbasa Bizualem Wakuma, Wu She-Huang, Su Wei-Nien, Hwang Bing Joe
Nano-Electrochemistry Laboratory, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
ACS Appl Mater Interfaces. 2022 Aug 17;14(32):36644-36655. doi: 10.1021/acsami.2c09040. Epub 2022 Aug 4.
A zinc metal anode for zinc-ion batteries is a promising alternative to solve safety and cost issues in lithium-ion batteries. The Zn metal is characterized by its high theoretical capacity (820 mAh g), low redox potential (0.762 V SHE), low toxicity, high abundance on Earth, and high stability in water. Taking advantage of the stability of Zn in water, an aqueous Zn ion battery with low cost, high safety, and easy-to-handle features can be developed. To minimize water-related parasitic reactions, this work utilizes a highly concentrated salt electrolyte (HCE) with dual salts─1 m Zn(OTf) + 20 m LiTFSI. MD simulations prove that Zn is preferentially coordinated with O in the TFSI anion from HCE instead of O in HO. HCE has a broadened electrochemical stability window due to suppressed H and O evolution. Some advanced and / analysis techniques have been applied to evaluate the morphological structure and the composition of the formed passivation layer. A dual-ion full Zn||LiMnO cell employing HCE has an excellent capacity retention of 92% after 300 cycles with an average Coulombic efficiency of 99.62%. Meanwhile, the low concentration electrolyte (LCE) cell degrades rapidly and is short-circuited after 66 cycles with an average Coulombic efficiency of 96.91%. The battery's excellent cycling performance with HCE is attributed to the formation of a stable anion-derived solid-electrolyte interphase (SEI) layer. On the contrary, the high free water activity in LCE leads to a water-derived interfacial layer with unavoidable dendrite growth during cycling.
用于锌离子电池的锌金属阳极是解决锂离子电池安全性和成本问题的一种有前途的替代方案。锌金属的特点是具有高理论容量（820 mAh g）、低氧化还原电位（0.762 V SHE）、低毒性、在地球上的高丰度以及在水中的高稳定性。利用锌在水中的稳定性，可以开发出具有低成本、高安全性和易于处理特点的水系锌离子电池。为了最大限度地减少与水相关的寄生反应，这项工作采用了一种含有双盐（1 m Zn(OTf) + 20 m LiTFSI）的高浓度盐电解质（HCE）。分子动力学模拟证明，锌优先与来自HCE的TFSI阴离子中的O配位，而不是与HO中的O配位。由于抑制了H和O的析出，HCE具有拓宽的电化学稳定性窗口。已经应用了一些先进的分析技术来评估形成的钝化层的形态结构和组成。采用HCE的双离子全Zn||LiMnO电池在300次循环后具有92%的优异容量保持率，平均库仑效率为99.62%。同时，低浓度电解质（LCE）电池迅速退化，并在66次循环后短路，平均库仑效率为96.91%。该电池在HCE下的优异循环性能归因于形成了稳定的阴离子衍生固体电解质界面（SEI）层。相反，LCE中高的自由水活性导致了在循环过程中不可避免地出现枝晶生长的水衍生界面层。
