Boosting Low Temperature Performance of Lithium Ion Batteries at −40°С Using a Binary Surface Coated Li₃V₂(PO₄)₃ Cathode Material

Severe capacity degradation at low temperatures (<−20°С) hampers wide applications of lithium-ion batteries (LIBs) in consumer electronics and electric vehicles. Existing works are dedicated to electrolyte modification because that electrolyte controls both Li⁺ transportation and interfacial reaction. However, the efforts on electrolytes are always hard to balance rate performance and low-temperature capacity due to their high viscosity. Herein, a binary coating layer for Li₃V₂(PO₄)₃ cathode material without changing electrolyte formulation is proposed, which significantly improves the high-rate capability and low-temperature performance of batteries. YPO₄ nanoparticles are in situ formed in the amorphous surface carbon layer under the reaction between Li₃V₂(PO₄)₃ and Y(NO₃)₃ during post-thermal treatment. The C+YPO₄ binary coating reduces the side reactions of Li₃V₂(PO₄)₃ at high voltage. In addition, the binary surface coating also improves the interfacial kinetics of the electrode at low temperatures. Benefiting from these advantages, the Li₃V₂(PO₄)₃ cathode material can cycle stably at ultra-high rates up to 50 C. In addition, the capacity retention at −20 and −40 °С are improved to 89.1% and 75.7%, respectively. This binary surface-coated Li₃V₂(PO₄)₃ cathode material shows promising application potential in low-temperature LIBs.