Surface modification offers an alternative strategy to improve both ageing resistance and electrochemical performance of cathode materials for lithium-ion batteries.From the viewpoint of real application,surface modif...Surface modification offers an alternative strategy to improve both ageing resistance and electrochemical performance of cathode materials for lithium-ion batteries.From the viewpoint of real application,surface modification of the cathode materials should be designed with scientificity,effectiveness,low cost,less Li+leaching,and remained tap density.In this contribution,a selective adsorption-involved in-situ growth of polyaniline(PANI)nanoparticles on LiNi_(0.5)Mn_(0.3)Co_(0.2)O_(2)(NMC532)has been designed through a room-temperature-and-pressure chemical vapor deposition technique.The selective growth of PANTI on NMC532 is based on theoretical computation results that multivalent Ni,Mn,and Co are capable of specifically conjugating and activating aniline molecules and,hence,initiating in-situ oxidation polymerization.With only trace amount of aniline monomer,the resulting PANI nanoparticles-inlaid NMC532 microparticles can endure four-month ageing in ambient atmosphere and exhibit improved electrochemical performance at both room temperature and 55℃ compared with pristine NMC532.The improved electrochemical performance of NMC532/PANI is attributed to the enhanced structural stability of NMC532 and inhibited side reactions related to Li_(2)CO_(3) formation,PVDF degradation,electrolyte decomposition,and transition-metal dissolution,owing to PANI modification.展开更多
采用高温固相法制备三元单晶正极材料LiNi0.5Mn0.3Co0.2O2(NMC532),并采用碳酸锆铵对其进行表面喷雾包覆,通过XRD、场发射电子扫描显微镜、能量色散光谱仪、电池充放电、电化学阻抗和循环伏安测试研究了碳酸锆铵喷雾包覆对材料结构和电...采用高温固相法制备三元单晶正极材料LiNi0.5Mn0.3Co0.2O2(NMC532),并采用碳酸锆铵对其进行表面喷雾包覆,通过XRD、场发射电子扫描显微镜、能量色散光谱仪、电池充放电、电化学阻抗和循环伏安测试研究了碳酸锆铵喷雾包覆对材料结构和电化学性能的影响.电化学性能测试表明,碳酸锆铵喷雾包覆可有效改善材料的高温循环性能,保持首圈库仑效率基本不变,但会牺牲材料的首圈放电比容量.相比于未喷雾包覆的三元单晶NMC532样品,喷雾包覆量为0.3%的NMC532样品,具有最优异的电化学性能,在55℃0.3C下的首次放电比容量为185.2 m Ah/g,库仑效率88.2%;在1.0C下经80次循环后容量保持率为95.5%.展开更多
基金financially supported by the Natural Science Foundation of Shandong Province(ZR2019MEM015 and ZR2017QB003)Young Taishan Scholar Program of Shandong Province(No.tsqn201909139)the Introduction and Cultivation Plan of Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Surface modification offers an alternative strategy to improve both ageing resistance and electrochemical performance of cathode materials for lithium-ion batteries.From the viewpoint of real application,surface modification of the cathode materials should be designed with scientificity,effectiveness,low cost,less Li+leaching,and remained tap density.In this contribution,a selective adsorption-involved in-situ growth of polyaniline(PANI)nanoparticles on LiNi_(0.5)Mn_(0.3)Co_(0.2)O_(2)(NMC532)has been designed through a room-temperature-and-pressure chemical vapor deposition technique.The selective growth of PANTI on NMC532 is based on theoretical computation results that multivalent Ni,Mn,and Co are capable of specifically conjugating and activating aniline molecules and,hence,initiating in-situ oxidation polymerization.With only trace amount of aniline monomer,the resulting PANI nanoparticles-inlaid NMC532 microparticles can endure four-month ageing in ambient atmosphere and exhibit improved electrochemical performance at both room temperature and 55℃ compared with pristine NMC532.The improved electrochemical performance of NMC532/PANI is attributed to the enhanced structural stability of NMC532 and inhibited side reactions related to Li_(2)CO_(3) formation,PVDF degradation,electrolyte decomposition,and transition-metal dissolution,owing to PANI modification.
文摘采用高温固相法制备三元单晶正极材料LiNi0.5Mn0.3Co0.2O2(NMC532),并采用碳酸锆铵对其进行表面喷雾包覆,通过XRD、场发射电子扫描显微镜、能量色散光谱仪、电池充放电、电化学阻抗和循环伏安测试研究了碳酸锆铵喷雾包覆对材料结构和电化学性能的影响.电化学性能测试表明,碳酸锆铵喷雾包覆可有效改善材料的高温循环性能,保持首圈库仑效率基本不变,但会牺牲材料的首圈放电比容量.相比于未喷雾包覆的三元单晶NMC532样品,喷雾包覆量为0.3%的NMC532样品,具有最优异的电化学性能,在55℃0.3C下的首次放电比容量为185.2 m Ah/g,库仑效率88.2%;在1.0C下经80次循环后容量保持率为95.5%.
