Low-temperature performance of Zn-modified graphite and hard carbon as anodes for lithium-ion batteries

Graphite has been the primary anode material in commercial lithium-ion batteries (LIBs) due to its lithium-like charge/discharge profiles and stable performance at room temperature. However, its effectiveness in low-temperature conditions remains a significant limitation for LIB applications. Hard carbon, an alternative anode material, offers potential advantages in low-temperature environments due to its unique porous structure and lithium storage mechanism. In this study, Zn-modified graphite and hard carbon electrodes were developed by partially substituting the conductive agent acetylene black with 1 wt% Zn. The impact of this Zn addition on the low-temperature performance of the anodes and solid electrolyte interphase (SEI) formation was systematically investigated, comparing Zn-modified electrodes to pristine Zn-free ones. The results indicate that Zn incorporation enhances electrochemical performance by improving electrical conductivity and fostering the development of a thin, uniform LiF-rich SEI layer, which reduces charge-transfer resistance and accelerates electrode activation at low temperatures.