Preparation And Electrochemical Properties Of Lithium Manganese Phosphate Cathode Material

Recently, the growing large needs for a clean environment and continuableenergy have attracted enormous attention to study on Lithium-ion batteries (LIBs),which are considered to be one of the most promising energy storage systems. Thenew types of the rechargeable Lithium-ion batteries with high voltage, high energydensity, long cycling life, non-memory effect and pollution-free have been intensivelyinterested.LiMnPO4is attracting increasing attention, because it has a higher theoreticalenergy density (697Wh kg-1=170mAh·g-1×4.1V) due to higher potential than that ofLiFePO4(586Wh kg-1=170mAh·g-1×3.45V). The potential of this material is alsowell within the stability window of well-known carbonate ester-based electrolytes. Inaddition, due to the low cost and environment friendly, LiMnPO4has greatapplication potential.In this paper, we will report the solid-state reaction and hydrothermal method forproducing LiMnPO4.We examines the factors that influencing the performance andstability of this material, and gropes the best respectively conditions.The effects of carbon content, calcination temperature and calcination time onLMP/C composite electrochemical performance were investigated and we optimizedthe best of synthesis process. The synthesized LiMnPO4/C composites have the bestelectrochemical performance when the carbon content is8wt.%, calcinationtemperature and calcination time is650℃and8h respectively. The initial dischargecapacity at0.1C is105mAh·g-1. On this basis, we improved the high-temperaturesolid-phase method. A surfactant (PVP) is admixed in the process of ball milling,which contributes to form uniform carbon coating and smaller particle, thus leading tothe enhanced electrochemical performance of LiMnPO4/C. The initial dischargecapacity at0.1C is134mAh·g-1.We optimized the process of hydrothermal to preparation LiMnPO4/C compositecathode. The effects of carbon coating, hydrothermal temperature, hydrothermal timeand the amount of CTAB on LiMnPO4/C composite electrochemical performancewere investigated and optimized the best of synthesis process. The synthesizedLiMnPO4/C composites have the best electrochemical performance when the amount of CTAB is half moles of LiMnPO4, the hydrothermal temperature, hydrothermaltime is190℃and24h respectively. The initial discharge capacity at0.05C,1C,5C is170,131,100mAh·g-1respectively and it has a good cycle performance.