Tackling realistic Li⁺ flux for high-energy lithium metal batteries

Electrolyte engineering advances Li metal batteries (LMBs) with high Coulombic efficiency (CE) by constructing LiF-rich solid electrolyte interphase (SEI). However, the low conductivity of LiF disturbs Li⁺ diffusion across SEI, thus inducing Li⁺ transfer-driven dendritic deposition. In this work, we establish a mechanistic model to decipher how the SEI affects Li plating in high-fluorine electrolytes. The presented theory depicts a linear correlation between the capacity loss and current density to identify the slope k (determined by Li⁺ mobility of SEI components) as an indicator for describing the homogeneity of Li⁺ flux across SEI, while the intercept dictates the maximum CE that electrolytes can achieve. This model inspires the design of an efficient electrolyte that generates dual-halide SEI to homogenize Li⁺ distribution and Li deposition. The model-driven protocol offers a promising energetic analysis to evaluate the compatibility of electrolytes to Li anode, thus guiding the design of promising electrolytes for LMBs.

Shuoqing Zhang, Ruhong Li, Nan Hu, Tao Deng, Suting Weng, Zunchun Wu, Di Lu, Haikuo Zhang, Junbo Zhang, Xuefeng Wang, Lixin Chen, Liwu Fan, Xiulin Fan