Targeted stabilization of solid electrolyte interphase and cathode electrolyte interphase in high-voltage lithium-metal batteries by an asymmetric sustained-release strategy

High-voltage lithium (Li)-metal batteries with cell-level energy density over 350 Wh kg−1 are promising energy storage systems. However, the aggressive interphase chemistries associated with highly reactive Li-metal anode and high-voltage cathodes impede their practical applications. Herein, we demonstrate the targeted stabilization of solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) in high-voltage Li-metal batteries by asymmetrically sustained-releasing different additives. An asymmetric sustained-release film loaded with lithium bis-(oxalate)borate (LiBOB) and LiNO3 on each side is investigated as a proof-of-concept. The sustained-releasing of LiBOB and LiNO3 can maintain a localized concentration at the high-voltage cathode and Li-metal anode fronts respectively, thus forming a stable B-containing CEI and N-containing SEI. As such, issues like dendrites growth, parasitic side reactions and transition metals dissolution under high-voltage are addressed simultaneously. Based on this strategy, the 30 μm Li|LiNi0.5Co0.2Mn0.3O2 (4.1 mAh cm−2) batteries deliver a capacity retention of 80% after 173 cycles under a cut-off voltage of 4.5 V.