Preparation And Electrochemical Properties Of Materials In Lithium Ion Battery

Because of its high energy density, good cycling performance and good safetyperformance, Li-ion battery is widely applied, including in mobile phones, laptops,electronic watches and digital cameras. In recent years, the focus of research in lithiumbattery is mostly concentrated on the improvement of its positive and negative materials,also for LiNi_1/3Co_1/3Mn_1/3O₂cathode material and the silicon anode materials. In thispaper, ternary cathode material is prepared and its process is optimized using ofsolid-state method and the sol-gel method based on existing research. And theelectrochemical workstation is also used in analysis and research. In addition, theperformance of the P-type silicon anode material is also studied.1.The materials were prepared by solid-state method and optimal synthesis processof using of singe factor were as follows: Synthesis temperature was900℃, roastingtime was15h, the ratio of Li:M was1.1:1, the best initial specific capacity was175mAh/g. Orthogonal experimental analysis showed that optimal synthesis process ofusing of singe factor were as follows: Synthesis temperature was900℃, roasting timewas20h, the ratio of Li:M was1.1:1, the calcination temperature was the mostimportant factors of affect the lithium-ion battery discharge capacity, and the sinteringtemperature was the most secondary factor. And increasing the amount of lithium androasting time also could enhance the capacity, but it could only be a weak enhance.2.After activation, the initial discharge capacity of the sintered product with rawmaterial tablet increased from169.7mAh/g to225mAh/g, the initial discharge capacityof the sintered product with powder material increased from149mAh/g to175mAh/g.With the help of Zview software, fitting impedance curve, the equivalent circuit modeland model impedance values was obtained. The results showed that the activated cellhas lower Reand higher Rsfvalues. The diffusion coefficient of the electrode inlithium-ion battery was calculated with Chronoamperometry and the result show that,the diffusion coefficient of the sintered product has improved after activation.3.The materials were prepared by sol-gel method and the optimum synthesis wasthat the sintering temperature was900℃, sintering time was15h, the ratio of Li:M was 1.1, the best capacity was187.2mAh/g and its retention rate was90.9%after cycle35times. Impedance test results show that the resistance of the material was low; CV testresults show that the material has a good reversibility. Compared with the sol-gelmethod, the material obtained buy solid-phase method has higher income capacity, andlower cycling and reversibility performance.4.The cycling performance of P-Si anode was excellent and its capacity remainedsteady at530mAh/g up to the45th cycle. Measurement of EIS showed that the diffusioncoeffcient of lithium ion in the P-Si anode was higher than in amorphous Si films.Comparison of SEM observation before and after the cycles, the size of P-Si particleswas the same, indicating that the P-Si was in favor of suppressing volume expansionand inhibiting the pulverization of P-Si anode.