Advanced Materials and Chemistries for Electrochemical Energy Storage Devices

The objective of this proposal is to develop advanced battery chemistries that allow batteries to operate safely at specific energies higher than 100 Wh/kg & energy densities over 600 Wh/l, or at power levels above 5kW/kg. The phosphate based LiMPO4 (M = Fe, Mn, Ni, and Co), cathodes are found to be attractive because of the stable nature of the olivine-type structure. Having a PO43− polyanion with a strong P–O covalent bond provides not only excellent cycle-life but also a safe system that is resistant to overcharge, thermal degradation and oxygen evolution. This stability reduces the risk of failure propagation in the high energy and high power batteries of interest to the AirForce. The robust covalent bonding of PO43−, however, reduces the compounds’ conductivities, and olivines require additional treatment with conductive aids to perform at useful rates. Yardney Technical Products proposes to develop a high voltage (>4.8V) olivine-type phosphate cathode and a suitable electrolyte system for high energy Li-ion batteries.