Surface-dipole-directed formation of stable solid electrolyte interphase

Solid electrolyte interphases (SEIs), which are formed by the decom-position of species in the inner Helmholtz plane (IHP) of the elec-trode surface, define the deposition behavior and cycling stability of Li metal anodes. Currently, the IHP is mainly tuned from electro-lyte aspects. In this work, we report that the dominating species in the IHP could be readily controlled via surface dipoles. By self -assembling heteroatomic conjugated molecules on a Cu foil, we con-structed a surface dipole that can increase the adsorption force of the Cu surface to anions, resulting in anion-rich IHP and an anion -derived SEI. The uniform nature of the self-assembled molecule layer and the robust anion-derived SEIs are conducive to uniform Li-deposited morphology, leading to a Li plating/stripping cycling Coulombic efficiency as high as 99.83%. This work sheds new light on tuning the electric double layer at the solid|liquid interface, which is of fundamental importance for the electrochemistry field.