Colloid Surf. A-Physicochem. Eng. Asp. 684 (2024), 133110
This
work reports an efficient and effective ex-situ carbon-coating strategy
for lithium iron phosphate (LFP) using supercritical CO2 (SCCO2) to improve its electrochemical performance. The SCCO2 possesses
unique features including gas-like diffusivity and zero surface
tension, which facilitate the penetration of carbon precursors among
active materials and enable the formation of high-quality carbon-coated
LFP (s-LFP/C). Compared to the conventional ball-milling process, the
carbon coating layer assisted by SCCO2 comprises
a higher fraction of graphitic carbon and fewer oxygen-derived
functional groups, both are advantageous for electron transport.
Additionally, the optimal s-LFP/C-containing half-cells reveal an
outstanding specific discharge capacity (ca. 99 mAh g−1 at
10 C) and cycle life (ca. 95% for 150 cycles at 0.5 C) contributed from
reduced charge-transfer impedance and comparable ionic diffusivity.
Taken together, the SCCO2-coating
technique highlighted herein offers a promising opportunity to build a
homogeneous and highly conductive carbon layer for boosting the
electrochemical characteristics of LFP cathode in lithium-ion batteries.