高镍三元材料LiNi _(0.8) Co_( 0.1 )Mn _(0.1) O _(2)(NCM811)因在高电压下具有高理论比容量而被广泛应用,与高镍材料如LiNi _(0.5) Co _(0.2) Mn _(0.3) O _(2)(NCM523)、LiNi _(0.6) Co _(0.2) Mn _(0.2) O _(2)(NCM622)等相比存在...高镍三元材料LiNi _(0.8) Co_( 0.1 )Mn _(0.1) O _(2)(NCM811)因在高电压下具有高理论比容量而被广泛应用,与高镍材料如LiNi _(0.5) Co _(0.2) Mn _(0.3) O _(2)(NCM523)、LiNi _(0.6) Co _(0.2) Mn _(0.2) O _(2)(NCM622)等相比存在循环性能差的缺陷。为解决这一问题,提出向碳酸酯电解液中加入电解液成膜添加剂三(三甲基硅烷)硼酸酯(TMSB),以提升NCM811/石墨软包电池的循环性能。结果表明,加入2 wt%TMSB可提高NCM811/石墨软包电池的容量保持率。通过理论计算及形貌表征发现,TMSB能够通过提前氧化还原成膜保护电池电极,从而改善电池循环性能。展开更多
LiNi0.8Co0.1Mn0.1O2(NCM811)|SiOx-graphite(SiO-Gr.)battery chemistry is of intensive attention because its achievable practical energy density is approaching impressively 300 Wh Kg^(-1).However,it still suffers rapid c...LiNi0.8Co0.1Mn0.1O2(NCM811)|SiOx-graphite(SiO-Gr.)battery chemistry is of intensive attention because its achievable practical energy density is approaching impressively 300 Wh Kg^(-1).However,it still suffers rapid capacity fades during repeated cycles,both chemical,electrochemical and mechanical irreversibility contribute.A comprehensive understanding behind the fading behavior of the cell chemistry is required before fully realize the benefits of this chemistry.Herein,the in-situ thickness variation is introduced as a diagnostic technique and is performed on 5-55 Ah NCM811|SiO-Gr cells.With the help of Li reference electrode and in-situ X-ray diffraction device,the correspondence between thickness variation and the electrode potential is carefully investigated.Firstly,the NCM811|SiO-Gr cell is characterized with the maximum cell thickness at around 80%state-of-charge(SOC)in the discharge process,rather than at 100%SOC.Secondly,the electrochemical behaviors during rate charge/discharge are diagnosed,and a Li platting signal is resolved from thickness variation profile at 2C.This work confirms that the thickness monitoring is a nondestructive and informative complement to conventional diagnostic techniques for failure analysis of pouch cells.展开更多
文摘高镍三元材料LiNi _(0.8) Co_( 0.1 )Mn _(0.1) O _(2)(NCM811)因在高电压下具有高理论比容量而被广泛应用,与高镍材料如LiNi _(0.5) Co _(0.2) Mn _(0.3) O _(2)(NCM523)、LiNi _(0.6) Co _(0.2) Mn _(0.2) O _(2)(NCM622)等相比存在循环性能差的缺陷。为解决这一问题,提出向碳酸酯电解液中加入电解液成膜添加剂三(三甲基硅烷)硼酸酯(TMSB),以提升NCM811/石墨软包电池的循环性能。结果表明,加入2 wt%TMSB可提高NCM811/石墨软包电池的容量保持率。通过理论计算及形貌表征发现,TMSB能够通过提前氧化还原成膜保护电池电极,从而改善电池循环性能。
基金funded by the Ministry of Science and Technology of China(No.2019YFE0100200,2019YFA0705703)the National Natural Science Foundation of China(No.22075064,No.21875057,U1564205 and 51706117)+1 种基金the Key-Area Research and Development Program of Guangdong Province(No.2020B090919005)the Tsinghua University Initiative Scientific Research Program(No.2019Z02UTY06).
文摘LiNi0.8Co0.1Mn0.1O2(NCM811)|SiOx-graphite(SiO-Gr.)battery chemistry is of intensive attention because its achievable practical energy density is approaching impressively 300 Wh Kg^(-1).However,it still suffers rapid capacity fades during repeated cycles,both chemical,electrochemical and mechanical irreversibility contribute.A comprehensive understanding behind the fading behavior of the cell chemistry is required before fully realize the benefits of this chemistry.Herein,the in-situ thickness variation is introduced as a diagnostic technique and is performed on 5-55 Ah NCM811|SiO-Gr cells.With the help of Li reference electrode and in-situ X-ray diffraction device,the correspondence between thickness variation and the electrode potential is carefully investigated.Firstly,the NCM811|SiO-Gr cell is characterized with the maximum cell thickness at around 80%state-of-charge(SOC)in the discharge process,rather than at 100%SOC.Secondly,the electrochemical behaviors during rate charge/discharge are diagnosed,and a Li platting signal is resolved from thickness variation profile at 2C.This work confirms that the thickness monitoring is a nondestructive and informative complement to conventional diagnostic techniques for failure analysis of pouch cells.
