Thermodynamic and Quantum Chemical Investigation and its Material Design of Highly Functional Oxide

高功能氧化物的热力学和量子化学研究及其材料设计

• 批准号: 14550803
• 负责人: IDEMOTO Yasushi
• 金额: $ 1.54万
• 依托单位: Tokyo University of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550803/
• 关键词: Lithium Secondary Battery; Positive electrode material; Thermodynamic data; First-principles_calculation; Electronic structure; Structure analysis; Powder neutron diffraction; Charge-discharge cycle performance; 量子化学計算; 中性子回折; サイクル特性

We investigated the relation between thermodynamic stability, crystal structures, electronic states and electrode performance of LiMn_<2-x>M_xO_4(M=Al, Ni, Co, Cr, Zn, Mg)as cathode materials for lithium secondary batteries.The cycle performance is improved by substitution of Mn with M.The heat of dissolution of these samples was measured by the solution calorimetry method.The enthalpy change per mole of atoms for the formation reaction, ΔH_R, were calculated from the heat of dissolution.The larger |ΔH_R| means a thermodynamically more stable sample.A more thermodynamically stable sample makes a stable crystal structure and leads to a good cycle performance.The crystal structure was determined by Rietveld analysis using powder neutron diffraction.The electron density distribution was obtained by XRD using MEM/Rietveld method and DV-Xα method.The electronic density maps of LiMn_<2-x>M_xO_4 shows the covalent bonding of Mn-O of LiMn_<2-x>M_xO_4 is stronger than that of LiMn2O4.On the other hands, we calculated that the net charge of each atom, the bond overlap population of Li-O, Mn-O, M-O, the density of states, and the electron density of LiMn_<1.75>M_<0.25>O_4 using first principles calculation by DV-Xα method.Li ****y always keeps high and the covalent bonding of Mn-O in the octahedron of each LiMn_<1.75>M_<0.25>O_4 is stronger than that of LiMn_2O_4.****ver, we investigated the electronic states of Li_yMn_<2-x>M_xO_4 dependence of Li content.We calculated the electronic states of Li_yMn_<1.75>M_<0.25>O_4 by DV-Xα method.The net charge of each atom, and the bond overlap populations of Mn-O and M-O were calculated.The strong covalency between Mn and 0 existed in the Li defect model and Li_yMn_<2-x>M_xO_4.The bonding change in Mn-O is small and maintained the spinel structure during the charge-discharge process by substitution of Mn with M.From these results, the stability of the host structure is important for cycle performance.

我们研究了热力学稳定性，晶体结构，电子状态和limn_ <2-x> m_xo_4（m = al，ni，ni，co，cr，zn，mg）作为锂二次电池的太极材料。从溶解的热量计算地层反应的原子ΔH_R。|ΔH_R|意味着在热力学上更稳定的样品。一种更热力学稳定的样品使晶体结构稳定，并导致良好的周期性能。晶体结构是通过使用粉末中子衍射的rietveld分析来确定的。通过mem/rietveld方法和DV-Xα方法，通过XRD获得电子密度分布。 Limn_ <2-X> M_XO_4的Mn-O比Limn2O4.4的MN-O更强大，我们计算出每个原子的净充电，Li-O，Mn-O，M-O的债券重叠的状态，状态密度，LIMN_ <1.75> m_ <0.25> o_4的债券密度，以及使用Limn_ <1.75> m_ <0.25> o_4的电气。始终保持较高和Mn-O在每个Limn_ <1.75> m_ <0.25> O_4的八面体中的共价键强，而O_4比Limn_2O_4。 li_ymn_ <1.75> m_ <0.25> O_4通过DV-Xα方法。计算每个原子的净电荷，键的粘结重叠型MN-O和M-O的种群是MN和0的强大价值。LIE_YMN_和LI_YMN_ <2-x> m_xo__的键合中存在于LIE_XO>m_xo_4。通过用MN取代MN的过程，从这些结果中，宿主结构的稳定性对于循环性能很重要。

项目成果

井手本 康: "5V級Li二次電池用正極活物質LiMn_<1.5>Ni_<0.5>O_4の酸素量と電極特性"電気化学および工業物理化学. 70巻,8号. 587-589 (2002)

出本靖：“5V级Li二次电池正极活性物质LiMn_<1.5>Ni_<0.5>O_4的氧含量和电极性能”《电化学与工业物理化学》第70卷，第8期。587-589（2002）。

Y.Idemoto: "Dependence of Li content on Crystal Structure during the Charge-Discharge Process of LiMn_<1.5>Ni_<0.5>O_4 as a Cathode Materials for 5V Class Lithium Secondary Battery"Electrochemistry. Vol.71, No.12. 1142-1144 (2003)

Y.Idemoto：“作为5V级锂二次电池正极材料的LiMn_<1.5>Ni_<0.5>O_4充放电过程中Li含量对晶体结构的依赖性”电化学。

伊藤 由賀: "LiMn_<2-x>M_xO_4(M=Mn,Mg,Al,Co,Ni,Zn)のサイクル特性とMEM/Rietveld法および第一原理計算(DV-Xα法)による電子状態"電気化学および工業物理化学. 72巻1号. 20-26 (2004)

Yuga Ito：“通过 MEM/Rietveld 方法和第一性原理计算（DV-Xα 方法）研究 LiMn_<2-x>M_xO_4 (M=Mn,Mg,Al,Co,Ni,Zn) 的循环特性和电子态”化学与工业物理化学。第 72 卷，第 1 期。20-26 (2004)

伊藤 由賀: "実験および理論的手法によるLi二次電池用正極材料LiMn系酸化物の検討"表面. 41巻8号. 274-288 (2003)

Yuga Ito：“使用实验和理论方法研究 LiMn 基氧化物作为锂二次电池的正极材料”Surface，第 41 卷，第 8 期。274-288 (2003)。

Yasushi Idemoto: "Oxygen content and Electrode Characteristics of LiMn_<1.5>Ni_<0.5>O_4 as a 5V Class Cathode Material for Lithium Secondaly battery"Electrochemistry. Vol.70,No.8. 587-589 (2002)

Yasushi Idemoto：“LiMn_<1.5>Ni_<0.5>O_4作为5V级锂二次电池正极材料的氧含量和电极特性”电化学。