Conductive NaTi2(PO4)3/C nanocomposite by spray drying for enhanced sodium energy storage

Abstract

NaTi₂(PO₄)₃ is a promising sodium-ion battery material, but its poor electrical conductivity limits practical applications. In this paper, we controlled the drying and curing process of the precursor powder through spray drying to regulate the material’s morphology and structure. High-temperature sintering was used to control the crystallinity of the material and the formation of the carbon coating, thereby enhancing the electrochemical performance. Ultimately, NaTi₂(PO₄)₃/C nanoparticles were evenly coated with an amorphous carbon layer, which acts as a protective and conductive layer, enhancing structural stability, reducing side reactions, and improving the cycle life of the battery. The NaTi₂(PO₄)₃/C anode exhibits high reversible capacity, stable cycling performance, and good rate capability, with a discharge capacity of 127 mAh·g⁻¹ at 0.5 C, maintaining 95 mAh·g⁻¹ after 1000 cycles at 5 C, and retaining 81 mAh·g⁻¹ even at a high rate of 50 C. Additionally, it shows excellent performance in aqueous sodium-ion batteries, with a discharge capacity of 101 mAh·g⁻¹ at 2 C and a capacity retention of 73% after 100 cycles. The carbon coating is a promising method to enhance the conductivity of NASICON-type materials, offering opportunities for future applications in sodium-ion batteries.