Yao Hong, Li Yuhang, Chen Zibo, Chen Jianyu, Du Cheng-Feng, Chen Yingqian, Chen Junze, Wong Ming Wah, Zhao Jin, Yuan Du
College of Materials Science and Engineering, Changsha University of Science and Technology, 960, 2nd Section, Wanjiali RD (S), 410004, Changsha, Hunan, China.
State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, 210023, Nanjing, Jiangsu, China.
Angew Chem Int Ed Engl. 2024 Dec 9;63(50):e202411056. doi: 10.1002/anie.202411056. Epub 2024 Oct 28.
Reversibility of metallic Zn anode serves as the corner stone for the development of aqueous Zn metal battery, which motivates scrutinizing the electrolyte-Zn interface. As the representative organic zinc salt, zinc trifluorosulfonate (Zn(OTf)) facilitates a broad class of aqueous electrolytes, however, the stability issue of Zn anode remains crucial. The great challenge lies in the lack of Zn anode protection by the pristinely formed surface structure in aqueous Zn(OTf) electrolytes. Accordingly, an electrochemical route was developed to grow a uniform zinc trifluorosulfonate hydroxide (ZTH) layer on Zn anode as an artificial SEI, via regulation on metal dissolution and strong coordination ability of zinc ions. Co-precipitation was proposed to be the formation mechanism for the artificial SEI, where the reduction stability of OTf anion and the low-symmetry layer structure of ZTH was unmasked. This artificial SEI favors interfacial kinetics, depresses side reactions, and well maintains its integrity during cycling, leading to a prolonged lifespan of Zn stripping/plating with a high DOD of ~85 %, and an improved cycling stability of ~92 % retention rate for VO/Zn cell at 1 A g. The unveiled role of anion on Zn anode drives the contemplation on the surface chemistry for the blooming aqueous rechargeable battery.
金属锌阳极的可逆性是水系锌金属电池发展的基石，这促使人们对电解质-锌界面进行深入研究。作为典型的有机锌盐，三氟甲磺酸锌（Zn(OTf)₂）可用于多种水系电解质，然而，锌阳极的稳定性问题仍然至关重要。巨大的挑战在于，在水系Zn(OTf)₂电解质中，初始形成的表面结构缺乏对锌阳极的保护作用。因此，通过调控金属溶解和锌离子的强配位能力，开发了一种电化学方法，在锌阳极上生长一层均匀的三氟甲磺酸锌氢氧化物（ZTH）层作为人工固体电解质界面（SEI）。共沉淀被认为是人工SEI的形成机制，其中揭示了OTf⁻阴离子的还原稳定性和ZTH的低对称层结构。这种人工SEI有利于界面动力学，抑制副反应，并在循环过程中很好地保持其完整性，从而使锌的剥离/电镀寿命延长，深度放电容量（DOD）高达约85%，并提高了VO₂/Zn电池在1 A g⁻¹时的循环稳定性，保留率约为92%。阴离子在锌阳极上所揭示的作用促使人们对蓬勃发展的水系可充电电池的表面化学进行思考。
