| High performance battery electrodes are critical component of modern technology. Three dimensionally ordered macroporous (3DOM) Li 4Ti5O12 and Ag4V2O 6F2 are two active materials with properties that make them each excellent high performance battery electrodes for their respective applications. 3DOM Li4Ti5O12 is synthesized by infiltration of poly(methylmethacrylate) (PMMA) colloidal crystal templates with soluble aqueous precursors titanyl oxalate and lithium acetate. 3DOM Li4Ti 5O12 with different wall thicknesses, and thus different wall structures, are synthesized by single step infiltration of the precursors into the template voids by capillary action, followed by drying and calcination.; The 3DOM architecture markedly improves the rate capability of Li 4Ti5O12 and the wall thickness of the 3DOM structure also affects the rate capability of the material. Three electrodes with 75%, 100% and 125% filling fractions were studied, and electrochemical data show that performance declines as wall thickness increases. In the 75% filled sample, the capacity at the lowest rate is 167 mAh/g and at the highest rate is 155 mAh/g, which is higher than most Li4Ti5O12 capacities at low rates. The rate capability of the 100% filled sample was also better than that of non-porous Li4Ti5O12; the 125% filled sample behaved similarly to the non-porous material. The enhanced rate capability results from the interconnected network of nanometer scale walls, which create short lithium diffusion distances and better contact with the electrolyte. The low angle grain boundaries between interconnected crystallites improve electronic conduction and reduce polarization.; Ag4V2O6F2 is a new oxide fluoride phase, which has been characterized by single crystal X-ray diffraction and evaluated as a primary lithium battery cathode for implantable cardioverter defibrillators. Ag4V2O6F2 (SVOF) exhibits two characteristic regions within the discharge curve. The first plateau, at 3.52 V, is the silver reduction potential and it is nearly 300 mV higher than that of the commercial primary battery material, Ag2V 4O11 (SVO). The second sloped region around 2.3 V is from reduction of the vanadium oxide fluoride framework. The material has a nominal capacity of 251 mAh/g with 148 mAh/g above 3 V. |
