Planting CuGa2 seeds assisted with liquid metal for selective wrapping deposition of lithium

Uncontrollable lithium dendrite growth can cause serious performance deterioration of lithium metal batteries (LMBs). Here, we propose a mode of selective wrapping deposition of Li mediated by in-situ planted CuGa2 seeds on liquid metal painted Cu collector. The lithiophilic CuGa2 layer significantly reduces the nucleation barrier during Li plating and acts as a uniform conductive host to confine Li mass within its grain boundaries. Asymmetric Li/CuGa2@Cu cells enable a long-term cycling over 220 cycles with a high coulombic efficiency of ~99% at 3 mA cm−2, a low voltage hysteresis (~100 mV at 5 mA cm−2), and high endurability on current density up to 10 mA cm−2 and areal capacity up to 5 mAh cm−2. The alloying of rich Ga with Cu collector is responsible for the low nucleation barrier and the tight bonding of CuGa2 seeds with substrate enables the high endurance of Li deposition cycling. The ductile liquid metal can be directly dropped on Li foil to form uniform LixGa alloying layer. With the self-migration of gallium on Li surface, symmetric [email protected] cells can cycle for 1000 h and full cells can maintain a highly reversible capacity of 110 mAh g−1 for high-load LiFePO4 cathode (12 mg cm−2). Liquid metal protection provides more possibilities for Li anode modification design, considering its controllable surface tension, fluidity and low-toxic nature.