Advancing Anode-Free Lithium Metal Battery via Environmentally Resilient Lithium Oxalate as a Low-Voltage Prelithiation Additive

Due to the exceptionally high energy density and compatibility with the existing battery manufacturing process, the anode-free lithium metal battery (AFLMB) exhibits significant potential for practical implementation. However, the lifespan of the AFLMB is severely limited by the highly reactive lithium metal anode. Although enhanced cycling stability has been achieved through advanced electrolyte and anode design, the poor initial Coulombic efficiency (ICE) inevitably leads to reduced capacity in AFLMB. In this study, the environmentally resilient lithium oxalate (Li 2 C 2 O 4 ) is introduced as a cathode prelithiation additive for AFLMB to offer in situ lithium supply. Complete decomposition of Li 2 C 2 O 4 within 4.5 V is realized with an optimized conductive network. Characterizations including SEM, XRD, and XPS reveal that the adoption of Li 2 C 2 O 4 does not adversely impact the cathode significantly, with the electrochemical performance remaining essentially unaltered. Consequently, the capacity degradation of AFLMB is markedly suppressed, with the 20% Li 2 C 2 O 4 -containing LFP|sodium alginate@Ag@Cu full battery exhibiting stable operation for 130 cycles without any noticeable capacity degradation.