High-performance Na 3 V 2 (PO 4 ) 3 cathode material embedded in three-dimensional porous carbon derived from tea leaves

Among various known positive electrode materials for sodium-ion batteries, polyanion-type cathode materials are the preferred system for high stability and high safety of sodium-ion batteries. Especially, Na 3 V 2 (PO 4 ) 3 has enormous development potential. This work uses tea leaves as a novel biomass carbon source to uniformly grow Na 3 V 2 (PO 4 ) 3 crystals into a three-dimensional porous carbon framework through a facile sol–gel method. The prepared Na 3 V 2 (PO 4 ) 3 /C material presents a three-dimensional porous carbon conductive network structure, and its electrochemical performance is significantly improved compared to the pristine material. The Na 3 V 2 (PO 4 ) 3 /C material exhibits a high initial discharge specific capacity of up to 110.6 mAh g −1 at 0.1 C within 2.0–4.0 V.