Ju Zhengyu, Zheng Tianrui, Marschilok Amy C, Takeuchi Esther S, Takeuchi Kenneth J, Yu Guihua
Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
Institute of Sustainability, Electrification and Energy, Stony Brook University, Stony Brook, NY, 11794, USA.
Adv Mater. 2025 Jul 20:e08743. doi: 10.1002/adma.202508743.
Lithium-ion batteries, as sustainable alternatives to fossil fuels, are in great demand for powering modern society. Their energy density can further be significantly improved by using Li metal anodes; however, Li metal suffers from the critical challenges of unstable solid-electrolyte interphase (SEI) along with uncontrollable dendritic Li growth. Here, a universal electrolyte design principle is proposed and demonstrated by using suspension electrolytes with charged additives. The solvation structure of Li ions can be regulated, as negatively charged additives show strong electrostatic interaction with Li ions, leaving them weakly solvated in the electrolyte. Moreover, negatively charged additives carrying Li ions can be locally concentrated at the surface of the Li metal, enhancing their ability to regulate solvation and improve interfacial mobility, beneficial for the formation of inorganic-rich SEIs and compact Li deposition. Accordingly, Li||Li symmetric cell demonstrates >500 h stable cycling at 2 mA cm and 2 mA h cm and Li||LiFePO cell shows 97% capacity retention after 400 cycles in 1C. The universality of this design is further demonstrated in various negatively charged suspension electrolyte systems. Such an electrolyte design rationale can shed light on the development of advanced electrolyte systems for realizing high-energy-density and long-duration metal battery systems.
锂离子电池作为化石燃料的可持续替代品，在为现代社会供电方面有巨大需求。通过使用锂金属阳极，其能量密度可进一步显著提高；然而，锂金属面临着固体电解质界面（SEI）不稳定以及锂枝晶生长不可控等关键挑战。在此，通过使用带有带电添加剂的悬浮电解质，提出并证明了一种通用的电解质设计原则。锂离子的溶剂化结构可以得到调控，因为带负电的添加剂与锂离子表现出强烈的静电相互作用，使锂离子在电解质中溶剂化程度较弱。此外，携带锂离子的带负电添加剂可在锂金属表面局部富集，增强其调控溶剂化和改善界面迁移率的能力，有利于形成富含无机成分的SEI和致密的锂沉积。相应地，锂||锂对称电池在2 mA cm和2 mA h cm下展示出>500小时的稳定循环，锂||磷酸铁锂（LiFePO）电池在1C倍率下400次循环后容量保持率为97%。这种设计的通用性在各种带负电的悬浮电解质体系中得到了进一步证明。这样一种电解质设计原理可为开发用于实现高能量密度和长续航金属电池系统的先进电解质体系提供启示。
