Porous polyimide separator promotes uniform lithium plating for lithium‐free cells

Abstract

Abstract Electrospun polyimide (PI) separators were found to reduce the charge‐transfer resistance of Li plating/stripping and the overpotentials of Li nucleation/growth onto Cu foils in the 1.2 M LiPF6/(ethylene carbonate/dimethyl carbonate = 1/1) electrolyte without any additives in comparison with polyethylene (PE) separators. Lithium deposition through the PI separator led to the formation of a granular morphology of 15–30 µm in diameter compared to lithium dendrites using PE. A similar trend of lithium deposition was observed in LiFePO4//Cu cells. The PI separator was found to enhance the discharge capacity and cycle life of Li plating/stripping in the Li//Cu and LiFePO4//Cu cells containing 40 µl electrolytes, verifying that the PI separator provides dendrite inhibition capability for the lithium‐metal‐free cells.

Keywords

• copper substrate
• dendrite inhibition
• lithium plating/stripping
• polyimide
• separator