materialsstudio在电池材料研究中的应用.doc

电池材料结构设计与模拟 孙 洁! ! 天津大学! 1 Why Li ion battery research? Li ion batteries are currently a part of everyday life: ～10 Wh ～2,500 Wh ～85,000 Wh World ~10TWh 2 How does a Li-ion battery work? ?? Li must be more stable in cathode than anode Voltage ?? Electrodes must accomodate sufficient Li Capacity ?? Electrons/ions must be extractable from electrodes Conductivity Voltage x capacity = Energy 3 Why use Density functional theory (DFT) methodology? need: Constituent Atoms Approximate Structure DFT Get: Total Energy Magnetization Forces Single particle energy levels (band structure) Derive: Voltage Conductivity Stability (structural, chemical) Activation barriers Cheap, reliable way to scan materials for suitability Understanding of the underlying physics/chemistry 4 What fundamentally determines voltage? What determines level of d-states? i) Oxidation state of electrochemically active ion ii) Atomic weight of electrochemically active ion iii) Local structure (bonding with oxygen) iv) Long range structure (dimensionality) For Li-ion batteries ΔE 5 eV 5 Calculating Voltage i) Structural How does “host” change as Li is added or subtracted ? graphite LiCoO2 LiFePO4 ii) Electronic How hard is it to extract/add an electron? 6 (In reality, these two cannot be decoupled) 算例目录 ?? 新电池体系的电位、容量预测 算例1. Cu0电化学插层Bi2Se3的超导性能研究 ?? 锂离子电池（负极） 算例2.新型碳纳米材料超理论容量的解释 算例3.宿主碳基材料的“灌锂”性能研究 ?? 磷负极 (锂／钠离子电池) 算例4.黑磷异向反应特性的研究 算例5.磷／碳复合材料的结构设计（2D限域；界面限域） 算例6.开发新型化学反应方法的理论依据 ?? 锂硫电池 算例7.锂硫电池中功能性隔膜修饰材料的选择 算例8.硫正极修饰材料的选择与性能评价 7 算例1. Cu0电化学插层Bi2Se3的超导性能研究 ——“电池”电位、比容量预测 研究背景 Chemical method 4% Cu JACS, 134, 13773-13779 (2012) CuxBi2Se3, x 0.15 Phys. Rev. Lett. 104 (2010) 057001 8 算例1. 超导材料CuxBi2Se3的电化学调控 ——“电池”电位、比容量预测 1.电化学插层方法预测 电位的差异的原因？ V = ? E(Cux2Bi2Se3)? E(Cux1Bi2Se3)? (x2 ? x1)E(Cu) (x2 ? x1)e 9 算例1. 超导材料CuxBi2Se3的电化学调控 ——“电池”电位、比容量预测 2.插层结构的验证：实验与模拟结合 10 算例1. 超导材料CuxBi2Se3的电化学调控 ——“电池”电位、比容量预测 3. 电子结合 能变化的理 论解释 11 算例1. 超导材料CuxBi2Se3的电化学调控 ——“电池”电位、比容量预测 12 算例1. 超导材料CuxBi2Se3的电化学调控 ——“电池”电位、比容量预测 1