Achieving a dendrite-free lithium metal anode through lithiophilic surface modification with sodium diethyldithiocarbamate

Abstract

The deposition of Li on most common metal substrates has a large nucleation overpotential, resulting in intermittent and nonuniform nucleation and deposition, which is prone to generating dendrites and dead Li. A modified layer with good lithiophilicity can promote Li nucleation and achieve dendrite-free and homogeneous Li deposition. In this work, we applied surface monolayer self-assembly (MSA) modification on the most commonly used Cu foil current collector with sodium diethyldithiocarbamate (DDTC) to obtain DDTC/Cu electrodes. After the electrochemical loading of Li, a Li metal composite anode with a homogeneous Li deposition layer was obtained (Li/DDTC/Cu). This surface modified matrix containing N and S functional groups has a strong interaction with Li, which can realize homogeneous and dendrite-free Li deposition, and further lead to a longer cycle life of the anode. A high coulombic efficiency of over 99% can be maintained for Li plating/stripping cycling. When matched with the LiFePO₄ cathode, the full cell can reach a capacity retention rate of 83% after 300 cycles. This simple electrode preparation method for constructing a lithiophilic matrix through MSA provides a new way for achieving the desired composition and modification of Li metal anodes, which is expected to become a competitor in the field of energy storage in the future.