Scalable fabrication of a large-area lithium/graphene anode towards a long-life 350 W h kg−1 lithium metal pouch cell

Abstract

Volume expansion and “dead Li” accumulation in the Li anode forbid the development of practical pouch-cell type Li metal batteries (pLMBs). Thus, development of highly reversible and long-life Li metal anodes is of great importance in this area. Herein, a facile thermally initiated conversion method is proposed to fabricate a Li/graphene composite anode (Li@G) by a heating induced local reaction among Li powder, graphene and PVDF. Using simple mixing–coating–drying–heating procedures, a large-area Li@G anode can be prepared in a roll-to-roll way with a film casting machine. The detailed morphology and functions of the LiC₆ skeleton in this composite anode on alleviating “dead Li” accumulation are confirmed. Failure analysis and morphology characterization demonstrate the improvement in reducing cell resistance and concentration polarization by using this novel Li anode. As a result, a 0.55 A h pLMB (Li@G/NCM811) strictly following practical conditions can cycle stably 140 times due to the improved reversibility of Li stripping/plating. Moreover, a 2.6 A h pLMB (Li@G/NCM811) delivers a high energy density of 356 W h kg⁻¹ (based on the whole cell) with a high capacity retention of 70% for 100 cycles. The scalable preparation method of the advanced Li@G anode presented in this paper makes promising progress in design and fabrication of Li composite anodes for practical pLMBs.