Regulating lithium-ion flux in the solid electrolyte interphase layer to prevent lithium dendrite growth on lithium metal anode

• Plasma modification negatively functionalized the PP separator's surface. • O 2 plasma modified sample had the best electrochemical and battery performance. • Surface negativity regulated the diffusivity of cations(anions) in the electrolyte. • Increasing surface negativity prevented dendritic form deposition of lithium-ions. • The negative surface charge was compensated for the decrease in tensile strength. High theoretical capacity and lowest electrochemical potential make lithium metal anode the most suitable anode material for lithium-ion batteries (LIBs). However, Lithium dendrite growth on lithium metal anode hinders proper discharge capacity and practical cycle life of LIBs. It dues to high lithium-ion flux in the solid electrolyte interphase (SEI) layer versus low diffusion in anode structure. Herein, we employ argon and oxygen plasma to modify commercial polypropylene separator surface to negatively functionalize the separator surface and discuss the influence of increasing surface negative charge on lithium dendrite growth and formation of SEI layer. Comparing electrochemical and battery performance of unmodified and plasma modified separators demonstrates, increased negative surface charge prevents lithium dendrite growth and makes a uniform and thin SEI layer due to lowering lithium-ion flux in the SEI layer. More precisely, we conduct that coulombic interaction between plasma modified separator's surface and electrolyte's cations (anions) can regulate lithium-ion flux in the SEI layer, preventing lithium dendrite growth and making thin homogeneous SEI layer on lithium metal anode structure.