Solvation layer effects on lithium migration in localized High-Concentration Electrolytes: Analyzing the diverse...

Localized high-concentration electrolytes (LHCEs) offer a new methodology to improve the functionality of conventional electrolytes. Understanding the impact of antisolvents on bulk electrolytes is critical to the construction of sophisticated LHCEs. However, the mechanism of how antisolvent modulates the electrochemical reactivity of the solvation structure in LHCEs remains unclear. In this work, the key correlation between the physicochemical properties of antisolvents and their corresponding Lithium-ion battery (LIBs) systems has been elucidated by comprehensive multiscale theoretical simulations combined with experimental characterizations. Nine antisolvents (chain ethers and cyclic non-ethers) are investigated in a typical lithium bis(fluorosulfonyl)imide/1,2-dimethoxymethane (LiFSI/DME) system. It is highlighted that the relative molecular masses of antisolvents in the same class are positively correlated with the density. The viscosity of a liquid mixture consisting of DME and antisolvent in the same class is positively correlated with the magnitude of the interaction energy between them. Additionally, the self-diffusion coefficient of Li⁺ is also positively correlated with the sum of the interaction energies between Li⁺-DME and Li⁺-FSI^-, which is also affected by the class of antisolvent. These results provide deep insights into the behavior and properties of LHCEs, which help to advance the design of high-performance LIBs.