Improving electrochemical performance of Na3(VPO4)2O2F cathode materials for sodium ion batteries by constructing conductive scaffold

Abstract

Room-temperature sodium ion batteries (SIBs) are considered as a potential candidate to substitute the high-cost lithium ion batteries due to the high abundance of sodium resources; however, it is still a challenge to develop high power/energy density and stable cathode materials for SIBs. Recently, Na3(VPO4)2O2F (NVPOF) expresses strong competitiveness under high working voltage in sodium storage field because of its eximious structural stability and high energy density. Nevertheless, the intrinsically poor electronic conductivity hinders its electrochemical performance. Herein, 1 D carbon nanotube (CNT) and 2 D polyaniline (PANI) are utilized as self-templates to prepare NVPOF@CNT/PANI polyhedrons via a facile and cost-efficient synthetic route. The highly conductive CNT/PANI scaffold can offer a quick electron transfer pathway. Benefiting from this unique design, NVPOF@CNT/PANI shows excellent electrochemical performance：delivering a high specific capacity of 125.3 mAh g−1 at 0.5 C, excellent rate property of 62.7 mAh g−1 at 20 C, and long lifespan of 2000 cycles with the capacity of 44.1 mAh g−1 at 10 C. This work for NVPOF gives a promising method to prepare the high-performance cathode material for sodium-ion battery, and this approach can also extend to optimize other battery materials.