采用两步干混-球磨方法制备了石墨烯掺杂改性的锂离子电池LiFePO_4/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2复合正极材料,实现LiNi_(0.8)Co_(0.15)Al_(0.05)O_2材料的高容量和高安全性。借助X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X...采用两步干混-球磨方法制备了石墨烯掺杂改性的锂离子电池LiFePO_4/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2复合正极材料,实现LiNi_(0.8)Co_(0.15)Al_(0.05)O_2材料的高容量和高安全性。借助X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)以及电化学测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,石墨烯的存在实现了Li Fe PO4材料在LiNi_(0.8)Co_(0.15)Al_(0.05)O_2材料表面的完全包覆,形成致密的包覆层,进一步抑制LiNi_(0.8)Co_(0.15)Al_(0.05)O_2与电解液之间的副反应,提高活性材料利用率和循环性能。三者之间构成导电网络,加快电子渗透和传输,提高倍率性能。Li Fe PO4质量分数为20%的Li Fe PO4-Graphene/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2样品具有最佳的容量性能和长循环性能,0.1C时放电容量达到202.5 m Ah·g^(-1),3C时放电容量仍然可保持在160.5 m Ah·g^(-1)。50℃在2.8~4.3 V,0.5C下循环100次后,容量保持率为91.9%,优于LiNi_(0.8)Co_(0.15)Al_(0.05)O_2和LiFePO_4/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2样品的72.9%和82.0%。展开更多
<正> The dissolved quantity of 10 Na2O.18B2O3-72 SiO2(mol%) glass was measured and the-change of the un-and attacked surface of this glass by water was observed with photometric analysis and IRRS.ESCA methods. T...<正> The dissolved quantity of 10 Na2O.18B2O3-72 SiO2(mol%) glass was measured and the-change of the un-and attacked surface of this glass by water was observed with photometric analysis and IRRS.ESCA methods. The corrosion mechanism of this glass was put forward. It has shown that the process which this glass was corroded in the water could be divided into two stages with the dissolved quantity-square root of time behaviour. Firstly the stable colloid film containing[BSiO4]-constitution was formed due to the leaching of Na2O and[BO3/2] trihedral constitution from the surface during the period of 0~120min. Secondly the Na2O and[BO3/2] trihedral constitution was leached through the loose colloid film continually, the colloid film was destroied because [BSiO4]- was isolated and dissolved daring the period of 120~180min.展开更多
以碳酸钠为沉淀剂,乳酸钠为络合剂合成碳酸盐前驱体,950℃烧结制备了Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2(x=0,0.02,0.04,0.06)系列材料,探讨元素含量变化对材料的结构、形貌、充放电性能的影响。研究结果表明:随着x的增大,材料的...以碳酸钠为沉淀剂,乳酸钠为络合剂合成碳酸盐前驱体,950℃烧结制备了Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2(x=0,0.02,0.04,0.06)系列材料,探讨元素含量变化对材料的结构、形貌、充放电性能的影响。研究结果表明:随着x的增大,材料的晶格常数c/a比值增加,层状结构更加完整。当x=0.02时,该材料的充放电性能最优,其首次放电容量为261.0 m A·h/g,0.5C下循环100次后的放电容量仍有189.9 m A·h/g,容量保持率高达98.85%,2C倍率下放电容量最高达到157.6 m A·h/g。进一步增大x值时,由于Co含量的上升,使得更多的Co3+/4+2g轨道与O2–2p轨道发生带隙重叠,从而使得材料的比容量和循环性能下降。展开更多
基金supported by the Natural Science Foundation of Shanghai the Science and Technology Commission Shanghai Municipality(19ZR1475100)the Equipment Pre-research Fund(61407210207)the Sichuan Science and Technology Program(2021JDRC0015)。
文摘采用两步干混-球磨方法制备了石墨烯掺杂改性的锂离子电池LiFePO_4/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2复合正极材料,实现LiNi_(0.8)Co_(0.15)Al_(0.05)O_2材料的高容量和高安全性。借助X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线光电子能谱(XPS)以及电化学测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,石墨烯的存在实现了Li Fe PO4材料在LiNi_(0.8)Co_(0.15)Al_(0.05)O_2材料表面的完全包覆,形成致密的包覆层,进一步抑制LiNi_(0.8)Co_(0.15)Al_(0.05)O_2与电解液之间的副反应,提高活性材料利用率和循环性能。三者之间构成导电网络,加快电子渗透和传输,提高倍率性能。Li Fe PO4质量分数为20%的Li Fe PO4-Graphene/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2样品具有最佳的容量性能和长循环性能,0.1C时放电容量达到202.5 m Ah·g^(-1),3C时放电容量仍然可保持在160.5 m Ah·g^(-1)。50℃在2.8~4.3 V,0.5C下循环100次后,容量保持率为91.9%,优于LiNi_(0.8)Co_(0.15)Al_(0.05)O_2和LiFePO_4/LiNi_(0.8)Co_(0.15)Al_(0.05)O_2样品的72.9%和82.0%。
文摘<正> The dissolved quantity of 10 Na2O.18B2O3-72 SiO2(mol%) glass was measured and the-change of the un-and attacked surface of this glass by water was observed with photometric analysis and IRRS.ESCA methods. The corrosion mechanism of this glass was put forward. It has shown that the process which this glass was corroded in the water could be divided into two stages with the dissolved quantity-square root of time behaviour. Firstly the stable colloid film containing[BSiO4]-constitution was formed due to the leaching of Na2O and[BO3/2] trihedral constitution from the surface during the period of 0~120min. Secondly the Na2O and[BO3/2] trihedral constitution was leached through the loose colloid film continually, the colloid film was destroied because [BSiO4]- was isolated and dissolved daring the period of 120~180min.
文摘以碳酸钠为沉淀剂,乳酸钠为络合剂合成碳酸盐前驱体,950℃烧结制备了Li1.2[Mn0.52-0.5xNi0.20-0.5xCo0.08+x]O2(x=0,0.02,0.04,0.06)系列材料,探讨元素含量变化对材料的结构、形貌、充放电性能的影响。研究结果表明:随着x的增大,材料的晶格常数c/a比值增加,层状结构更加完整。当x=0.02时,该材料的充放电性能最优,其首次放电容量为261.0 m A·h/g,0.5C下循环100次后的放电容量仍有189.9 m A·h/g,容量保持率高达98.85%,2C倍率下放电容量最高达到157.6 m A·h/g。进一步增大x值时,由于Co含量的上升,使得更多的Co3+/4+2g轨道与O2–2p轨道发生带隙重叠,从而使得材料的比容量和循环性能下降。
