Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China.
University of Chinese Academy of Sciences, 100190, Beijing, P. R. China.
Small Methods. 2023 Jun;7(6):e2300392. doi: 10.1002/smtd.202300392. Epub 2023 Apr 25.
Water-in-salt (WIS) electrolyte is considered as one of most promising systems for aqueous zinc batteries (AZBs) due to its dendrite-free plating/stripping with nearly 100% Coulombic efficiency. However, the understanding of the interfacial mechanisms remains elusive, which is crucial for further improvements in battery performance. Herein, the interfacial processes of solid electrolyte interphase (SEI) formation and subsequent Zn plating/stripping are monitored by in situ atomic force microscopy and in situ optical microscopy. The live formation of uniform and compact LiF-rich SEI in WIS systems could induce the uniform hexagonal Zn deposition with preferential orientation growth in the (002) crystal plane, showing excellent plating/stripping reversibility. In contrast, the SEI formed in 1 m zinc bis(trifluoromethylsulfonyl)imide (Zn(TFSI) ) is uneven and rich in inert ZnO, adversely triggering the dendrite propagation and successive "dead" Zn accumulation in repeated deposition/dissolution cycles. This work provides an in-depth understanding of the relationship between SEI evolution and Zn-deposited behaviors in AZBs, possibly stimulating more research on rational composition design and structural optimization of solid/liquid interface for advanced rechargeable aqueous multivalent-ion batteries.
水系锌电池（AZBs）因具有无枝晶电镀/剥离和近 100%库仑效率而被认为是最有前途的水系锌电池体系之一。然而，界面机制的理解仍然难以捉摸，这对于进一步提高电池性能至关重要。在此，通过原位原子力显微镜和原位光学显微镜监测了固体电解质界面（SEI）形成和随后的 Zn 电镀/剥离的界面过程。在 WIS 体系中，均匀致密的富 LiF 的 SEI 的原位形成可以诱导具有（002）晶面择优取向生长的均匀六方 Zn 沉积，表现出优异的电镀/剥离可逆性。相比之下，在 1 m 锌双（三氟甲基磺酰基）亚胺（Zn（TFSI））中形成的 SEI 不均匀且富含惰性 ZnO，不利地触发了枝晶的生长和在反复沉积/溶解循环中连续的“死”Zn 的积累。这项工作深入了解了 SEI 演变与 AZBs 中 Zn 沉积行为之间的关系，可能会激发更多关于先进可充电多价离子电池的固/液界面的合理组成设计和结构优化的研究。
