A path towards high lithium-metal electrode coulombic efficiency based on electrolyte interaction motif descriptor
Ruhong Li, Xiaoteng Huang, Haikuo Zhang, Jinze Wang, Yingzhu Fan, Yiqiang Huang, Jia Liu, Mingyao Yang, Yuan Yu, Xuezhang Xiao, Yuanzhong Tan, Hao Bin Wu, Li‐Wu Fan, Tao Deng, Lixin Chen, Yanbin Shen, Xiulin Fan
Abstract
Abstract The fundamental interactions and the as-derived microstructures among electrolyte components play a pivotal role in determining the bulk and interfacial properties of the electrolytes. However, the complex structure-property relationships remain elusive, leading to uncontrollable physicochemical characteristics of electrolytes and unsatisfied battery performance. Herein, we propose two interaction motif descriptors to quantify ion-solvent interactions spanning electrostatic to dispersion regimes. These descriptors are highly relevant to salt dissolution, phase miscibility, and electrode-electrolyte interface chemistries. Guided by the principle of minimizing ion-solvent and solvent-solvent interactions while ensuring sufficient salt dissociation, a representative electrolyte, i.e ., lithium bis(fluorosulfonyl)imide dissolved in trimethyl methoxysilane and 1,3,5-trifluorobenzene with a molar ratio of 1:2.5:3.0, is designed, which achieves ~99.7% (±0.2%) Li plating/stripping Coulombic efficiency and endows 4.5 V Li||LiCoO 2 with 90% capacity retention after 600 cycles at 0.2 C/0.5 C charge/discharge rate. Notably, Cu||LiNi 0.5 Co 0.2 Mn 0.3 O 2 pouch cells with this electrolyte sustain over 100 stable cycles. By establishing quantitative relationships between interaction motifs and electrolyte functionalities, this work provides a universal framework for rational electrolyte design, paving the way for highly reversible lithium metal batteries.