V₂O₅ Loaded on SnO₂ Nanowires for High‐Rate Li Ion Batteries

Abstract

The growing demand for high-power applications such as electric vehicles, hybrid electric vehicles, and other power-supply devices has triggered signifi cant research efforts on high-energy and power-density energy-storage devices. [1][2][3][4][5] Among the energystorage devices, electrochemical supercapacitors can deliver high power, but they suffer from low energy density. [ 5 ] Lithium batteries (LiBs) with their high energy density have attracted considerable attention. [6][7][8][9] However, for use as a versatile power source, it is still a challenge to achieve a high-power density compared with supercapacitors. [ 2-4 , 6 ] In achieving a high power density, rapid ionic and electronic diffusion in electrode materials are necessary. [ 3 ] Recently, many strategies, such as reducing the electrode materials to the nanoscale size, coating or mixing with more conductive materials, and doping of electrode materials with foreign atoms have been developed to improve the power density. [ 3 , 4 , 6 , 10 ] In particular, an ultrafast discharge rate as high as 400 C was achieved by Ceder et al. [ 6 ] However, none of these methods provide a single silver bullet. The strategies mentioned above suffer from disadvantages such as poor cycling stability and the requirement of a high percentage of carbon black. [ 3 , 6 , 11 , 12 ] Therefore, there is currently an impending need to improve the performance of lithium batteries. V 2 O 5 is a very-promising electrode material as it offers the attractive advantages of low-cost, abundant sources and better safety. [13][14][15][16] Furthermore, Cui et al. have reported very fast (360 C) Li insertion into V 2 O 5 nanoribbons. [ 1 ] Dunn et al. and many other researchers have tried to improve the performance of V 2 O 5 by combining it with more-conductive materials like carbon, nickel and other materials to achieve better rate capability. [17][18][19][20][21] However, the performance is still unsatisfactory. For instance, V 2 O 5 /carbon composites have been reported to suffer from low cycling stability. [ 19 ] This also happens to Ni-V 2 O 5 ⋅ n H 2 O nanocable arrays. [ 21 ] Inspired by previous studies, we propose and realize a simple strategy of coating V 2 O 5 on SnO 2 nanowires to achieve high-power-density and high-energydensity LiBs. [ 19 , 21 , 22 ] In coin-cell measurements, with electrodes composed of these SnO 2 /V 2 O 5 core/shell nanowires (SVNs), a high specifi c capacity, an excellent rate capability and cycling stability are achieved. Furthermore, the temperature dependent performance is discussed systematically. Figure 1 shows the synthesis strategy for the SVNs. Firstly, the SnO 2 nanowires were synthesized using chemical vapor deposition. Then, V 2 O 5 was coated on the SnO 2 nanowires by pyrolysis of vanadyl-acetylacetonate (VO(acac) 2 ). Figure 1 schematically illustrates the idea and motivation, namely, the utility of the better conductivity of SnO 2 nanowires and the short diffusion distance of the thin V 2 O 5 layer. [ 1 , 22 ] Figure 2 a and b show fi ...

Electrospun Hierarchical CaCo2O4 Nanofibers with Excellent Lithium Storage Properties

“…However, even though many different synthetic methods have been for such architectures, most of these generally lead to the formation of 1D hierarchical heterostructures through solution methods. [8][9][10][11] Therefore, the development of facile and simple methods suitable for the fabrication of novel 1D nanomaterials still remains as a great challenge. Recently, as a kind of promising technique, electrospinning has been widely used as a convenient and cost-effective method to generate a variety of 1D nanomaterials with unique morphologies.…”

Nanoparticles Encapsulated in Porous Carbon Matrix Coated on Carbon Fibers: An Ultrastable Cathode for Li‐Ion Batteries

“…As references, Rct of the V2O5 nanoparticle electrode ( Figure S12a) increased obviously from 1.4 to 4.5 kΩ, and similarly, Rct of the V2O5 nanosheet array electrode increased from 71 to 168 Ω during the cycling process from 100th to 5000th cycle ( Figure S12b), which should be associated with the deterioration of electron transport due to the formation of disconnected clusters by aggregation of nanoparticles and gradual array collapse during cycling. [32,46,49] Moreover, Rs of the V2O5 nanosheet array electrode increased from 6.4 to 22.5 Ω from 100th to 5000th cycle, which could be caused by the dissolution of active materials into electrolyte during cycling processes. In comparison with the V2O5 nanoparticle and the V2O5 nanosheet array electrodes, the V2O5/3DC-CFs composite shows the smallest change in Rct during long cycling.…”

“…[17,29] Recently, it was shown that direct growth of V2O5 array structures on a current collector can substantially reduce the interparticle resistance and contact resistance, and leads to improved capacity and cyclic stability. [30][31][32] However, the low areal loading of the V2O5 array structures (~0.7 mg cm -2 ), hindered their practical application. [33] Moreover, collapse of the V2O5 array structures upon repeated charge/discharge cycling is another important problem to be addressed for high-performance LIBs.…”

Heterogeneous Nanostructured Electrode Materials for Lithium-Ion Batteries – Recent Trends and Developments

“…The good performance is explained by electric double layer capacitance of large surface area and high rate lithium insertion to V 2 O 5 gel. Recently, Yan et al (2011) have adopted a simple gas-phase-based method to synthesize V 2 O 5 loaded SnO 2 nanowires on the stainless-steel substrate (Figures 23a and b). V 2 O 5 loaded SnO 2 nanowires exhibit a high rate capability and very good cycling stability ( Figure 23c).…”