锂离子电池新型正极材料研究进展.pptVIP

Cycling performance of Li1.2+x[Ni0.25Mn0.75]0.8-xO2 (0?x?4/55) * Increasing Li content enhanced cycleability of materials. * * 2) Synthesis and electrochemistry of layered cathode materials Li1.2(Ni0.4Mn0.4)1-x-y(Co0.4Mn0.4)x(Ni0.2Mn0.6)yO2 (0?x+y?1) Li1.2Ni0.2Mn0.6O2 Li1.2Ni0.4Mn0.4O2 Li1.2Co0.4Mn0.4O2 Li1.2Ni0.2Co0.133Mn0.467O2 (x=y=1/3) * Layered Li1.2(Ni0.4Mn0.4)1-x-y(Co0.4Mn0.4)x(Ni0.2Mn0.6)yO2 (x=y=1/3) materials Solid solution can be prepared easily among Li1.2Co0.4Mn0.4O2 (x=1, y=0), Li1.2Co0.4Mn0.4O2 (x=1, y=0) and Li1.2Ni0.2Mn0.6O2 (x=0, y=1), also indicating promising properties. * 200 250 230 240 240 240 Preliminary observed capacity in the triangle phase diagram Further work is under progross. * Advantage of Li3V2(PO4)3 against LiFePO4: about 20% higher energy density than LiFePO4: LiFePO4 –a theoretical capacity of 170mAh/g and average working voltage of 3.45V Li3V2(PO4)3 : a theoretical capacity of 197mAh/g and average working voltage of 3.7 V； good cycling performance comparable to LiFePO4, in view of small volume change due to smaller difference in ionic radio of V3+/V4+/V5+ in stable NASICON-related structure than that of Fe2+/Fe3+ in olivine structure； better rate capability than LiFePO4 due to better ionic and electronic conductivity ； good thermal stability comparable to LiFePO4, due to NASICON-related structure ； better low temperature performance than LiFePO4; better ability to prevent from over-discharge due to another reversible redox couple of V3+/V2+; Possible to increase theoretical capacity by SiO44- substitution of PO43-. Li3V2(PO4)3 is considered as the most possible alternative of LiFePO4 in near future. 2. Li3＋xV2(PO4)3-x(SiO4)x /C (0≤x≤3) composite cathode materials The effect of different carbon precursors ( Pitch，Super P(carbon black), KS15(graphite),Vulcan-XC72(nanosized porous carbon) The effect of sintering temperature （650oC, 750oC, 850oC, 950oC ). The effect of carbon content ( 5%, 25%,