Enabling High-Energy Fast-Charging Lithium-Ion Lithium-Metal Batteries

Abstract

Enhancing the fast-charging capability and energy density of lithium-ion batteries (LIBs) is critical for advancing electric vehicle technologies. Conventional approaches rely on high negative-to-positive capacity ratios (N/P ≥ 1) to suppress dendritic lithium-metal plating, but this limits the full utilization of graphite’s capacity. A promising alternative is to enable reversible lithium-metal plating and stripping on graphite, forming a hybrid lithium-ion/lithium-metal anode that supports lower N/P ratios while boosting energy density, enabling fast charging and extending cycle life. In this work, we demonstrate that a high-volume PC-based electrolyte enables efficient cycling of Li-metal on graphite at an N/P ratio as low as 0.7. We show that stable and uniform solid-electrolyte interphase (SEI) formation is essential for sustaining Li-metal reversibility on graphite. The PC-based electrolyte supports stable cycling at both high (N/P = 1.16, 4C) and low (N/P = 0.7, 1C) ratios for over 1000 cycles. This study highlights the potential of PC-based electrolytes in stabilizing Li-metal on graphite and guides the design of electrolytes and SEI for high-performance lithium batteries.