Organic supramolecular protective layer with rearranged and defensive Li deposition for stable and dendrite-free lithium metal anode

Lithium (Li) metal anode is proposed to take on the heavy responsibility for high-energy Li metal batteries (LMBs). However, some severe obstacles such as uncontrolled growth of Li dendrites, infinite volume variation of Li deposition and low Coulombic efficiency are still big challenges. Herein, a copper foam covered with dense and rigid organic supramolecular protective layer (OSPL) with rearranged and defensive Li deposition is reported to effectively inhibit the formation of dendritic Li and suppress the depletion of Li metal and electrolyte, which is evidenced by optical/electron microscopy, in situ FTIR spectra, electrochemical probing and theoretical calculation. The composite matrix performs high Coulombic efficiencies of 98% for 250 cycles at 1 mA cm(-2) and enhanced cycling lifespan of 1300 h with low potential polarization (20 mV) for symmetric cell. Moreover, small nucleation overpotential (27.1 mV) benefits from attracting Li ions by massive polar functional groups in the organic supramolecular structure. When coupled with LiFePO4, full-cells display ultrahigh retention ratio (96.2%) and slow decay of specific capacity after 250 cycles at 0.5 C. Low voltage hysteresis reflects the improved kinetics and fast charge-transfer behavior during Li charging/discharging process. The strategy using OSPL provides a new insight for exploring high performance LMBs.