Solution Processing of V 2 O 5 -WO 3 Composite Films for Enhanced Li-Ion Intercalation Properties
- PDF / 966,911 Bytes
- 6 Pages / 595.32 x 841.92 pts (A4) Page_size
- 62 Downloads / 177 Views
1247-C11-14
Solution Processing of V 2 O 5 -WO 3 Composite Films for Enhanced Li-Ion Intercalation Properties
Chuan Cai1, Dongsheng Guan1, Ying Wang1 1
Department of Mechanical Engineering, Louisiana State University, Baton Rouge, LA 70803, U.S.A. ABSTRACT: We have employed a simple and novel solution processing method to prepare V2O5-WO3 composite films which demonstrate enhanced Li-ion intercalation properties for applications in lithium-ion batteries. It should be noted that this solution processing method employs precursors that only contain the elements of V, W, O and H, which avoids impurity elements such as Na that has been commonly used in other solution methods. The V2O5-WO3 composite films show enhanced Li-ion intercalation properties compared to pure V2O5 and WO3 films. For example, V2O5-WO3 film with a molar ratio V2O5/WO3 of 10/1 exhibits a discharge capacity of 254 mA•h/g, while the pure V2O5 film delivers a discharge capacity of 76 mA•h/g at a high current density of 1.33 A/g. Such enhanced Li-ion intercalation properties are attributed to the reduced crystallinity and increased porosity and surface area in the composite films. In addition, the chronopotentiometric curves of the V2O5-WO3 film with a mol ratio of 10:1 are distinctively different from those of pure oxide films and other composite films with different V2O5/WO3 mol ratios, suggesting a different Li-ion intercalation process in the V2O5-WO3 film with the mol ratio of 10/1. 1. INTRODUCTION Among various transition metal oxides that are capable of intercalating Li ions, vanadium pentoxide (V2O5) has attracted extensive attention for many years. 1,2 V2O5 can intercalate Li ions or other molecules due to its layered structure. 3 V2O5 has become a promising electrode material for rechargeable Li-ion batteries 4 and electrochromic displays. 5 However, the Li-ion diffusion coefficient (10-12 cm2/s) and the electronic conductivity (10-2 to 10-3 S/cm) in crystalline V2O5 are inherently too low to sustain a large specific capacity at high charge/discharge rates. 6 One way to improve the electrochemical performance of V2O5 is adding other electrochemically active species such as TiO2 into it.7 In this paper, we will fabricate V2O5-WO3 composite films which demonstrate enhanced Li-ion intercalation capacities compared to pure V2O5 and WO3 films. Most V2O5-WO3 composite films reported in literature have been studied for enhanced catalytic activity 8 or electrochromic performance. 9 In such composite films, WO3 is usually the major constituent and its catalytic or electrochroimc properties are improved by the V2O5 addition. There are few reports on the electrochemical properties of V2O5-WO3 composite films for applications in Li-ion batteries. Furthermore, V2O5-WO3 composite films are usually prepared by sol-gel
Downloaded from https://www.cambridge.org/core. Access paid by the UC Santa Cruz, on 22 Dec 2019 at 03:44:53, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/PROC-1247-C1
Data Loading...
