Tin oxide based materials that have been investigated over a number of years as anodes for rechargeable lithium-ion batteries have gravimetric and volumetric capacities of two to four times that of presently used graphite electrodes. However, the large capacity losses of up to 50 % that occur on the initial charge of these materials has so far precluded their practical application. The objective of this proposal is to develop new nanophase compositions and structures of metal oxides and nitrides that will significantly reduce or eliminate the initial capacity loss and lead to the realization of lithium-ion batteries with exceptionally high specific energies and energy densities. The approach is to dope tin and indium oxides and nitrides with Al. During synthesis of these materials, thermodynamics favors the formation of Al2O3 or AlN over SnOx or SnNx with the precipitation of some fraction of the Sn or In as nanoscale particles. The initial formation of the Al2O3 or AlN matrix will reduce the fraction of lithium that is irreversibly lost to formation of Li2O or Li3N on the initial charge step. The properties of the new materials will be investigated by a variety of electrochemical, ion and electron beam, and x-ray techniques. All Li and Li-Ion rechargeable batteries suffer from a significant drop in capacity, which occurs in the first charge/drain/recharge cycle due to an imbalance of the cathode/anode structure. In solid-state batteries this drop can be 40% of the total capacity of the cell. The advanced electrode materials at the focus of this proposal could reduce that fade by as much as 50%. This breakthrough could enable a drastic reduction in form factor for conventional rechargeable batteries resulting in increased performance and mobility of battery powered communications and weaponry systems. Beyond DoD requirements, advanced electrodes could also reduce the recycling burden of rechargeable batteries by as much as 25%.
Keywords: Nanostructure, Nanopowder, Nanocrystal, Battery, Electrode, Lithium, Energy Density, Electrolyte
