Potassium carbonate as film forming electrolyte additive for lithium-ion batteries

► The performance of graphite anode is improved in LiPF6-EC:DMC electrolyte with K2CO3. ► K2CO3 effectively suppresses the reduction of EC in the first lithiation process. ► The presence of K2CO3 modifies the morphology of SEI film to a worm mesh structure. ► This SEI is of better viscoelasticity to accommodate the volume changes of graphite.