铝掺杂LiNi0.8Co0.08Mn0.12O2梯度正极材料的制备及电化学性能

Preparation and Electrochemical Properties of Al-doped LiNi0.8Co0.08Mn0.12O2 Concentration Gradient Cathode Material

采用共沉淀法制备了梯度核壳前驱体Ni0.8Co0.08Mn0.12(OH)2,并通过混锂煅烧合成了LiNi0.8Co0.08Mn0.12O2梯度正极材料。分别使用干混法和沉淀法对梯度正极材料进行了Al的掺杂改性。XRD及电解液浸泡实验表明,Al掺杂可以稳定梯度正极材料的层状结构并降低阳离子混排度,抑制正极材料在电解液中的溶解,从而提高材料的电化学性能。经沉淀法掺杂后正极材料在25℃下1 C循环100次容量保持率由92.5%提高到94.5%,55℃下1 C循环50次容量保持率由91.3%提高到95.8%。

Concentration gradient core-shell precursor Ni0.8Co0.08Mn0.12(OH)2 was prepared by co-precipitation,and then concentration gradient cathode material LiNi0.8Co0.08Mn0.12O2 was synthesized by calcining with lithium hydroxide.The doping of aluminum was carried out by dry mixing and precipitation,respectively.The results of XRD and electrolyte immersion test indicate that aluminum doping can stabilize the layered structure of concentration gradient cathode materials,reduce the degree of cationic mixing,and also inhibit the dissolution of cathode materials in electrolyte.Therefore,the electrochemical properties of materials can be improved.After the concentration gradient cathode material is doped by precipitation,its capacity maintaining rate of 100 cycles at 25 ℃ under 1 C increases from 92.5% to 94.5%,and its capacity maintaining rate of 50 cycles at 55 ℃ under 1 C increases from 91.3% to 95.8%.