Enabling 6C fast charging of Li-ion batteries at sub-zero temperatures via interface engineering and 3D architectures

Addressing the trilemma between fast-charging, low-temperature operation, and high-energy-density electrodes is critical to advance Li-ion batteries. Here, we introduce a strategy that integrates 3D electrode architectures with an artificial solid-electrolyte interface (SEI) using atomic layer deposition of a solid electrolyte (Li₃BO₃-Li₂CO₃). These synergistic modifications enhance both mass transport and interfacial kinetics under low temperatures and fast charging, increasing the accessible capacity of thick electrodes (>3 mAh/cm²). To decouple the contributions from electrolyte transport and interfacial impedance, graphite/Li_xNi_yMn_zCo_aO (NMC) pouch cells were fabricated and their electrochemical performances were tested under low-temperature, fast-charging conditions. At a 6C-rate and a temperature of −10°C, these integrated electrodes enabled a >500% increase in accessible capacity and >97% capacity retention after 100 cycles, without Li plating. The capacity retention under low-temperature, fast-charging conditions was also dependent on the state-of-charge swing, highlighting the importance of the charging protocol to minimize Li plating.