表面活性剂对LiNi0.80Co0.15Al0.05O2的结构和性能影响  

Effect of Surfactant on Structure and Properties of LiNiCoAlO

作　　者：黄玲 王英 唐仁衡 肖方明 李文超 HUANG Ling;WANG Ying;TANG Ren-Heng;XIAO Fang-Ming;LI Wen-Chao(Guangdong Research Institute of Rare Metals and Guangdong Provincial Key Laboratory of Rare Earth Development and Application,Guangdong 510650,China)

机构地区：[1]广东省稀有金属研究所,广东省稀土开发及应用重点实验室,广州510650

出　　处：《无机化学学报》2020年第8期1465-1474,共10页Chinese Journal of Inorganic Chemistry

基　　金：广州市科技计划项目(No.201907010009);广东省科学院项目(No.2019GDASYL-0105057);广东省科学院能力建设专项项目(No.2017GDASCX-0110,2018GDASCX-0110);广东省科技计划项目(No.2017B030314081,2015B010116002)。

摘　　要：在共沉淀过程中添加表面活性剂聚乙二醇(PEG)或聚乙烯吡咯烷酮(PVP)分别合成类球形Ni0.80Co0.15Al0.05(OH)2前驱体,再与氢氧化锂(LiOH·H2O)氧化煅烧得到LiNi0.80Co0.15Al0.05O2(NCA)三元正极材料。利用X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)、循环伏安(CV)、交流阻抗(EIS)和充放电循环测试等对材料的结构、形貌、电化学性能等进行表征。结果表明:PEG和PVP的添加不影响材料中Ni、Co和Al元素的比例,能够促进一次晶粒长大和提高振实密度,能够促进正极材料层状结构发育进而提高正极材料的电化学性能。添加PEG、添加PVP和未添加表面活性剂合成正极材料的振实密度分别为2.07、1.86和1.40 g·cm-3,在0.2C充放电过程中首次放电比容量分别为210.8、188.9和173.0 mAh·g-1,以0.2C充电1C放电循环100次后电池容量保持率分别为78.8%、93.2%和82.7%,添加PEG和PVP的NCA材料表现出良好的电化学性能。A uniform LiNi0.80Co0.15Al0.05O2microsphere materials(NCA)with tap density of 1.86~2.07 g·cm-3were successfully prepared using co-precipitation method assisted by surfactants polyethylene glycol(PEG)or polyvinylpyrrolidone(PVP).Crystal structure,particles morphology and electrochemical features were evaluated through X-ray diffraction(XRD),transmission electron microscope(TEM),scanning electron microscope(SEM)cyclic voltammogram(CV),electrochemical impedance spectra(EIS)and charge/discharge studies.The results showed that the atomic ratio of Ni,Co and Al could not be affected in the materials which were synthesized with PEG or PVP and the materials had high tap density.The result of XRD showed that all the diffraction peaks of NCA materials were indexed to the pureα-NaFeO2layered structure which belonged to R3m space group.SEM images of precursors and NCA materials were obvious that the growth of primary grains was improved with the addition of PVP and PEG.The NCA obtained with the addition of PEG and PVP displayed a high discharge capacity of 210.8 and188.9 mAh·g-1at 0.2C,and showed good capacity retention of 78.8%and 93.2%after 100 cycles respectively which were better than that of NCA obtained without surfactant(173.0 mAh·g-1and 82.7%).EIS curves showed that electrochemical impedance of NCA-2 electrode least than NCA-1 and NCA-3 after 100 cycles.SEM images of positive plates after 200 cycles were obvious that positive plates synthesized by using PVP had least cracks and particle fragmentation.NCA-2 showed better capacity retention than NCA obtained with the addition of PEG and NCA obtained without surfactant.

关 键 词：电池 正极材料 共沉淀法 镍钴铝酸锂(NCA) 表面活性剂 聚乙二醇(PEG) 聚乙烯吡咯烷酮(PVP) 

分 类 号：O646.21[理学—物理化学]