Synthesis of 3-dimensional interconnected porous Na₃V₂(PO₄)₃@C composite as a high-performance dual electrode for Na-ion batteries

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Three-dimensional (3-D) interconnected porous Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> coated with carbon (NVP@C) is synthesised by a simple modified sol-gel method. When 15 wt% glucose is used as the carbon precursor, the obtained NVP@C15 composite exhibits excellent electrochemical performance as a cathode as well as an anode for sodium-ion batteries (SIBs). As a cathode, the NVP@C15 electrode delivers a high capacity of 116.9 mAh g<SUP>−1</SUP> at a rate of 1 C, which is close to its theoretical capacity. Even at a high rate of 20C, the NVP@C15 electrode exhibits an initial reversible capacity of 99.2 mAh g<SUP>−1</SUP> and a capacity retention of 77% after 6000 cycles. As an anode, the NVP@C15 delivers an initial reversible capacity of 85.8 mAh g<SUP>−1</SUP> at a rate of 1C. At higher rates of 10 and 20C, a remarkably good cyclability, with a capacity retention of 76% over 4000 cycles and 62% over 5000 cycles, respectively, is achieved. Furthermore, the full cell, composed of two symmetric NVP@C15 electrodes, exhibits an initial reversible capacity of 73 mAh g<SUP>−1</SUP> at a rate of 1C. In addition, capacity retentions of 88% after 100 cycles and 61% after 500 cycles are obtained at rates of 1C and 5C, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3-D interconnected porous Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C was synthesised by modified sol-gel method. </LI> <LI> 3-D interconnected porous structure provides easy diffusion pathways for Na ions. </LI> <LI> The uniform carbon coating on Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C provides better electronic conductivity. </LI> <LI> Na<SUB>3</SUB>V<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB>@C can be used as an anode and a cathode for sodium-ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>