Basu Raktima, Ghosh Subrata, Bera Santanu, Das A, Dhara S
Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam, 603102, India.
Water and Steam Chemistry Division, BARC Facility, Homi Bhabha National Institute, Kalpakkam, 603102, India.
Sci Rep. 2019 Mar 15;9(1):4621. doi: 10.1038/s41598-019-40225-1.
Vanadium oxides are anticipated as a high-performance energy storage electrode due to their coupled double layer and pseudo-capacitative charge storage mechanism. In the present work, we investigated the influence of different structural phases of as-grown VO nanoporous structure and corresponding oxidation states on the supercapacitor performance. This nanoporous structure facilitates fast ion diffusion and transport. It is shown that stoichiometric monoclinic VO, with V oxidation state of +4, provides superior charge storage capacity with a capacitance value of 33 mF/cm, capacitance retention of 93.7% and Coulombic efficiency of 98.2%, to those for VO structures with mixed oxidation states of V and V. A comparable high energy density is also recorded for the sample with all V. Scanning Kelvin probe microscopy results clarify further the formation of space charge region between VO and carbon paper. These key findings indicate the potentiality of binder-free single phase monoclinic VO porous structure towards the next-generation micro-supercapacitor application.
由于钒氧化物具有双电层和赝电容电荷存储机制，因此有望成为高性能储能电极。在本工作中，我们研究了生长态VO纳米多孔结构的不同结构相以及相应氧化态对超级电容器性能的影响。这种纳米多孔结构有利于快速的离子扩散和传输。结果表明，V氧化态为+4的化学计量单斜VO，与具有V和V混合氧化态的VO结构相比，具有更高的电荷存储容量，电容值为33 mF/cm，电容保持率为93.7%，库仑效率为98.2%。对于全V样品，也记录到了相当高的能量密度。扫描开尔文探针显微镜结果进一步阐明了VO与碳纸之间空间电荷区的形成。这些关键发现表明了无粘结剂单相单斜VO多孔结构在下一代微型超级电容器应用中的潜力。
