Dual-Conductive Li alloy composite anode constructed by a synergetic Conversion-Alloying reaction with LiMgPO4

With the increasing energy density demand for lithium-ion batteries, Li metal anode catches much attention owing to its ultrahigh theoretical capacity and low electrochemical potential. However, lithium is highly reactive and easily forms dendrites and fractures during deposition, which leads to low coulombic efficiency and severe safety problem. Thereby, suppressing the growth of Li dendrites to stabilize the Li/electrolyte interface is vital to lithium metal anode. Here, we introduce a strategy to construct a Li alloy/ion-conductor composite anode via a one-step conversion-alloying reaction. The pristine LiMgPO4 are converted to ion-conductive Li3PO4 and Mg, and Mg reacts with Li to form Li-Mg alloy, resulting in a final Li-LMP composite. The alloying and the generation of nanosized Li3PO4 not only enhance the mechanical strength of Li-LMP, making it more durable to the local stress during cycling, but also enhance ion transfer inside Li-LMP, showing a faster kinetic mass transfer process. As a consequence, Li-LMP shows promoted rate performance (LFP || Li-LMP could deliver 72 mAh g−1 at 10C) and cycle stability both in ether and carbonate electrolytes.