Hard Carbon Networks for Mitigating Graphite Lattice Strain Under Extreme‑Low‑Temperature Fast Charging

ABSTRACT

Low‐temperature fast charging of lithium‐ion batteries is primarily constrained by sluggish reaction kinetics and mechanical degradation of graphite anodes. Here, a kinetic–structural coordination strategy based on a 15 wt.% hard carbon (HC) percolating network embedded within the graphite matrix is proposed. This HC network functions as an ionic flux redistributor, effectively suppressing the high‐strain phase transition to stage 1 (LiC ₆ ) and reducing lattice strain, thereby protecting the graphite from mechanical pulverization. Moreover, the coordinated lithiation promotes the formation of a robust, LiF‐rich inorganic solid electrolyte interphase (SEI), which facilitates fast desolvation and prevents interfacial delamination. As a result, NCM523‖Graphite/HC pouch cells deliver 2250 cycles at −20°C under a 4C rate with 88% capacity retention, and maintain stable operation at 8C and −40°C. This network doping approach thus provides a scalable design principle for all‐climate, high‐power batteries intended for electric vehicle applications.