Vanadium batteries

One of the most important requirements that must be met is the membrane s ability to prevent excessive transfer of water from one half cell to the other. The preferential transfer of water can be a problem in the vanadium battery as one half-cell (the negative half cell in the case of cation exchange membranes) is flooded and becomes diluted, while the other becomes more concentrated, adversely affecting the overall operation of the cell. Most of the membranes show good initial water transfer properties, but their performance deteriorates with exposure to the vanadium solutions. Sukkar et al. ° evaluated various polyelectrolytes to determine whether they could improve the selectivity and stability of the membranes in the vanadium redox cell solutions. Both the cationic and anionic polyelectrolytes evaluated improved the water transfer properties of the membranes, although upon extended exposure to the vanadium electrolyte the modified membranes did not maintain their improved water transfer properties. The solvent based Nuosperse 657 modified membrane displayed exceptional properties initially but also failed to maintain its performance with extended exposure to the vanadium solutions. 

Explains signal transduction processes and related biology, biochemistry, and cell biology in a way that is accessible to chemists Provides detailed descriptions of vanadium batteries Describes recent advances in the applications of the lithium/silver vanadium oxide battery, particularly for medical applications... 

Based on their early fundamental research of all-VRFBs, Skyllas-Kazacos et al. [25] also first developed some commercial products, for example, a 1 kW vanadium redox battery (VRB) cell stack. By employing 1.5-2 M vanadium sulphate, sulphuric acid in both half-cells, over 85% of theoretical capacity and 70-80% energy efficiency was obtained. Then in 1994, a 4 kW/12 kWh vanadium battery was evaluated in a demonstration solar house by Thai Gypsum Products Ltd. in Thailand under a license lirom the UNSW [26]. 

R.L. Largent, M. Skyllas-Kazacos and J. Ghieng, Improved PV system p>erfor-mance using vanadium batteries. In Proceedings of the IEEE 23rd Photovoltaic Specialists Conference, Louisville, Kentucky, USA, May 1993. 

Conversion of fused pentoxide to alloy additives is by far the largest use of vanadium compounds. Air-dried pentoxide, ammonium vanadate, and some fused pentoxide, representing ca 10% of primary vanadium production, are used as such, purified, or converted to other forms for catalytic, chemical, ceramic, or specialty appHcations. The dominant single use of vanadium chemicals is in catalysts (see Catalysis). Much less is consumed in ceramics and electronic gear, which are the other significant uses (see Batteries). Many of the numerous uses reported in the Hterature are speculative, proposed. 

Redox flow batteries, under development since the early 1970s, are stUl of interest primarily for utility load leveling applications (77). Such a battery is shown schematically in Figure 5. Unlike other batteries, the active materials are not contained within the battery itself but are stored in separate tanks. The reactants each flow into a half-ceU separated one from the other by a selective membrane. An oxidation and reduction electrochemical reaction occurs in each half-ceU to generate current. Examples of this technology include the iron—chromium, Fe—Cr, battery (79) and the vanadium redox cell (80). 

Lithium-Vanadium Oxide 2.5.3 Lithium-Polyaniline Secondary Batteries Batteries... 

Lithium-vanadium oxide rechargeable batteries were developed as memory backup power sources with high reliability and high energy density. 

Table 11. Specifications of secondary lithium-vanadium oxide batteries...

Secondary Niobium Oxide-Vanadium Oxide Batteries... 

These batteries have vanadium oxide as the active material of the positive electrode, niobium oxide for the active material of the negative electrode, and an organic solvent for the electrolyte. Lithium ions enter the vanadium oxide from the niobium oxide during discharge, and lithium ions enter the niobium oxide from the vanadium... 

Secondary lithium-metal batteries which have a lithium-metal anode are attractive because their energy density is theoretically higher than that of lithium-ion batteries. Lithium-molybdenum disulfide batteries were the world s first secondary cylindrical lithium—metal batteries. However, the batteries were recalled in 1989 because of an overheating defect. Lithium-manganese dioxide batteries are the only secondary cylindrical lithium—metal batteries which are manufactured at present. Lithium-vanadium oxide batteries are being researched and developed. Furthermore, electrolytes, electrolyte additives and lithium surface treatments are being studied to improve safety and recharge-ability. 

One of the most important factors determining whether or not secondary lithium metal batteries become commercially viable is battery safety, which is affected many factors insufficient information is available about safety of practical secondary lithium metal batteries [91]. Vanadium compounds dissolve electrochemi-cally and are deposited on the lithium anode during charge-discharge cycle. The... 

Catalogue of lithium-vanadium oxide secondary batteries, Matsushita Battery Industrial Co., Ltd., 1996. 

Another type of redox flow battery that utilizes carbon electrodes and soluble reactants involving vanadium compounds in H2S04 is under evaluation [38,39] ... 

F—Magnesium Magnesium anode Carbon, vanadium pentoxide, and magnesium chloride Magnesium-based thermal batteries... 

---