Hybrid additive strategy with decoupled delivery pathways for synergistic interphase regulation in lithium metal batteries

This is the authors' abstract. We don't add key points for this paper.

Stabilizing both anode and cathode interphases is critical for the practical implementation of high-energy lithium metal batteries (LMBs) under high-voltage and lean-electrolyte conditions. Here, a hybrid additive incorporation strategy is presented to regulate interfacial chemistry. In this design, lithium nitrate (LiNO 3 ) is embedded within an electrospun polyacrylonitrile (PAN) interlayer, while lithium difluorobis(oxalato)phosphate (LiDFBOP) is introduced into the electrolyte, enabling decoupled additive delivery for interfacial stabilization. The LiNO 3 /PAN interlayer enables the formation of an ionically conductive, Li 3 N-rich solid-electrolyte interphase (SEI) that promotes uniform lithium deposition and enhances interfacial kinetics, while LiDFBOP facilitates the formation of inorganic-rich interphases that reinforce both the SEI and cathode-electrolyte interphase (CEI) and suppress electrolyte decomposition and transition-metal dissolution. As a result, Li‖NCM811 full cells with high cathode loading (3.5 mAh cm -2 ), ultrathin lithium metal anodes (20 μm, N/P = 1.17), and a cut-off voltage of 4.4 V achieve 79% capacity retention after 300 cycles. The hybrid system also demonstrates stable operation in pouch cells with energy densities of approximately 350 Wh kg -1 and 1070 Wh L -1 under lean electrolyte conditions of 2 g Ah -1 , as well as in anode-free cells. This work highlights that rational design of additive delivery pathways provides an effective strategy for constructing robust interphases in high-energy lithium metal batteries.