Enhancing Li⁺ Transportation at Graphite‐Low Concentration Electrolyte Interface Via Interphase Modulation of LiNO₃ and Vinylene Carbonate

ABSTRACT The solvent‐rich solvent sheath in low‐concentration electrolytes (LCEs) not only results in high desolvation energy of Li + , but also forms organic‐rich solid electrolyte interface film (SEI) with poor Li + conductivity, which hinders Li + transport at the electrode‐electrolyte interface and greatly limits the application of LCEs. Here, the electrochemical performance of the LCEs is enhanced by dual interfacial modification with LiNO 3 and vinylene carbonate (VC) additives. Results show that LiNO 3 is preferentially reduced at about 1.65 V to form an inorganic‐rich but incomplete SEI inner layer. The formation of Li 3 N and LiN x O y inorganic components helps to achieve rapid Li + transport in the SEI film, and the bare electrode surface caused by the incomplete SEI inner layer provides a place for the subsequent decomposition of VC. Then, at a lower potential of about 0.73 V, VC is reduced to generate the poly(VC)‐rich SEI outer layer, which provides lithium‐philic sites and greatly weakens the interaction between Li + and ethylene carbonate (EC). The interaction modulates the Li + solvation structure at the interface and reduces the desolvation energy of Li + . This ingenious design of the bilayer SEI film greatly enhances Li + transport and inhibits the decomposition of traditional carbonate solvents and the swelling of graphite. As a result, the electrochemical performance of the battery using 0.5 M LiPF 6 EC/diethyl carbonate (DEC) + 0.012 M LiNO 3 + 0.5 vt% VC is improved to a higher level than the one using 1.0 M LiPF 6 EC/DEC electrolyte. This research expands the design strategy and promising applications of LCEs by constructing a favorable SEI to enhance Li + transport at the electrode‐electrolyte interface.