Hybrid Li-rich cathodes for anode-free lithium metal batteries

Abstract

Anode-free lithium metal batteries (AFLMBs) are expected to achieve high energy density without Li anode. However, their capacities are fading quickly due to the lack of excessive Li resources from the anode side (N/P=0). Previously, cathode pre-lithiation to supplement excess Li in NCM811 was proven feasible to extend the battery lifespan of AFLMB, but deep lithiation suffers from crystal structure damage, resulting in short cycle life. Here, we proposed a hybrid Li-rich cathode by pre-lithiation of spinel structure material LiMn₂O₄ instead of Li-rich NCM compositing with NCM811, providing a new way to extend the lifespan of AFLMBs. During the first charge process, Li₂Mn₂O₄, as a pre-lithiation reagent, releases excess Li to form a lithium layer on the anode and revert to LiMn₂O_4, maintaining stable electrochemical reversibility in the following cycles. The anode-free lithium metal pouch cell employing a Li-rich hybrid cathode achieves a high energy density of nearly 400 Wh kg⁻¹ with 80 % capacity retention after 50 cycles.