Monday, 20 June 2016
Riverside Center (Hyatt Regency)
LiMPO4 (M=transition metal) has advantages of excellent structural and thermal stabilities, non-toxicity, low cost and excellent electrochemical properties. Among these compounds of materials, LiFePO4 is nontoxic and remarkably stable even in rough operating conditions. However, the problem of the low energy density of LiFePO4 resulting from its relatively low potential (~3.4 V) remains unresolved. LiMnPO4 has attracted tremendous attention due to the higher redox potential of Mn3+/Mn2+ vs. Li+/Li than that of Fe3+/Fe2+. However, there are numerous limitations related to its intrinsic electrochemical properties, mainly coming from the slow kinetics. Hence, the electrical conductivity is improved through carbon coating, Ag-embedded or the decrease in particle sizes in recent works. In this study, we find that the formation of a solid solution between LiFePO4 and LiMnPO4 is energetically favored, and each transition metal actively participates in the electrochemical reaction within a reasonable voltage range. Its electrochemical properties and phase stability are explored with continuous composition spread (CCS) radio frequency (RF) magnetron sputtering. We describe for Ag-doped olivine based cathode materials deposition on Pt/Ti/SiO2/Si substrates. The olivine compound Ag-doped thin film cathode materials was deposited by CCS RF magnetron sputtering. The CCS RF sputtering is a feasible method to deposit various compositions on a substrate with two targets. Two independent RF magnetron sputtering guns installed with LiFePO4 and Ag-doped LiMnPO4 targets are located vertically to a Pt/Ti/SiO2/Si substrates. Consequently, we have investigated the full range of LiFePO4 and LiMnPO4 compositions to find optimized composition with continuous composition spread RF magnetron sputtering.