Succinic anhydride as a deposition-regulating additive for dendrite-free lithium metal anodes

Li metal is a promising anode material for next-generation energy storage systems owing to its high theoretical capacity and low potential. However, uncontrollable Li dendrite growth during Li plating and stripping results in low coulombic efficiencies and severe safety hazards. Herein, succinic anhydride (SA), an inexpensive and simple molecule, is investigated as a deposition-regulating additive. The relationship between the Li electrodeposition overpotential and the solvation structure of Li ions was systematically analyzed. Electrochemical tests and theoretical calculations indicate that strong complexation between Li+ and SA changes the solvation structure of Li+ and increases the energy barrier for Li deposition, resulting in a higher overpotential for Li electrodeposition. This increase in overpotential is conducive to generating more nucleation sites, reducing the Li nucleus size, and forming smooth Li deposits. XPS results also show that the addition of SA facilitates the formation of an improved SEI structure. Therefore, symmetric Li/Li cells with 3.0 wt% SA in the electrolyte exhibit excellent electrochemical performance over 300 cycles at 1.0 mA cm−2 with a capacity of 0.5 mA h cm−2. Enhanced cycling performance is also observed in Li/LiNi0.8Co0.1Mn0.1O2 full cells. Thus, SA can significantly alter the Li plating behavior, affording a promising strategy for suppressing Li dendrite growth in Li-metal-based batteries.