Method of designing and modifying lithium ion battery cathode materials

• US 10,127,342 B2
• Filed: 04/08/2016
• Issued: 11/13/2018
• Est. Priority Date: 04/08/2016
• Status: Active Grant

• Current Assignee: Nano and Advanced Materials Institute Limited
• Original Assignee: Nano and Advanced Materials Institute Limited
• Inventors: Xin, Jianzhuo, Chau, Wing Yu, Jiang, Yingkai, Xu, Yeming, Ho, Kwok Keung
• Primary Examiner(s): Mudrick, Timothy A
• Application Number:
  US15/093,763
• Publication Number:
  US 20170293707A1
• Time in Patent Office: 949 Days
• Field of Search: 703 18
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 2300/004 Three solvents
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/382 Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/623 fluorinated polymers
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: H01M 4/661 : Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A method of designing and modifying electrode materials for a battery device is disclosed in this invention. The method includes constructing a first principle model for battery electrode material properties estimation and screening. The method also includes applying a structural and compositional modification on the first principle model. In some embodiments, the method includes developing a hybrid physical model to estimate the battery cell cycling behavior with the calculated and experimental parameters. The method and the simulation models have the advantage that both atomic level and physical structure will be considered for the battery electrode and its modified derivatives with small compositional or structural changes. Therefore, both the time consumption and accuracy for battery electrode material designing and modification for specific application requirements can be improved.

Claims

1. A method of designing and modifying electrode materials for a battery device, the method including a hybrid model combining an atomic-level model and a battery-level model, and comprising steps of:

1) building the atomic-level model, based on a first principle density function theory (DFT) or molecular dynamics, for a basic structure of the electrode material regarding to its composition and lattice structure;

2) calculating a series of factors selected from the group consisting of at least one lattice constant, slab thickness, system formation energy difference, lithium ion migration energy in lattice, lithium ion diffusion pathway, lithium ion diffusivity in lattice, lithium ion conductivity and specific heat capacity;

3) correlating the factors calculated by the atomic-level model with battery performance including structural stability, voltage, capacity, rate capability, and/or cycle performance;

4) selecting an electrode material with a certain composition and structure based on results of the atomic-level model as obtained in the step

     2) and the step

     3) for a potential battery application;

5) developing the battery-level model, based on a pseudo 2-dimensional (P2D) model with physical entities or an equivalent circuit model, for a battery cell based on the selected electrode material;

6) prioritizing importance of electrode material physical parameters by simulating and comparing cell charging and discharging behavior calculated by the battery-level model;

7) optimizing the prioritized electrode material physical parameters in the battery-level model according to a battery application requirement;

8) applying compositional and structural modifications in the atomic-level model based on the electrode material physical parameters selected in the step

     6);

9) optimizing the modifications in the atomic-level model with regarding to both the electrode material physical parameters and the battery performance; and

10) obtaining an optimal electrode material design for synthesizing electrode material as optimized in the step

     7) and the step

     9).

2. The method of claim 1, further comprising:

11) validating physical parameters of the synthesized electrode material by material characterization;

12) fabricating a battery cell, either a half cell or full cell, by using the synthesized electrode material;

13) validating performance the synthesized electrode material as a battery electrode by testing charging/discharging behavior of the battery cell.

3. The method of claim 1, wherein the electrode material is a cathode material and wherein the cathode material is selected from the group consisting of LiCoO₂, LiNiO₂, LiNi_xMn₁₋

x O₂, Li_1+zNi_xMn_yCo<sub>1−

x−

y</sub>O₂, LiNi_xCo_yAl<sub>1−

x−

y</sub>O₂, LiV₂O₅, LiTiS₂, LiMoS₂, LiMnO₂, LiCrO₂, LiMn₂O₄, LiFeO₂ and combinations thereof, wherein each x is independently from 0.1 to 0.6;

each y is independently from 0 to 0.8; and

each z is independently from 0 to 0.6.

4. The method of claim 1, wherein in the selection of electrode material of the step 4), a battery charging/discharging columbic efficiency is evaluated by the slab thickness, the battery structural stability is evaluated by the changes of lattice constant, lattice volume, and system energy in lithiation and delithiation, and the battery capacity are evaluated by the lithium ion migration energy and lithium ion diffusivity.

5. The method of claim 1, wherein the battery-level model comprises at least a battery cathode, a battery anode, a battery electrolyte, a separator, and a battery package, with the electrode material physical parameters, which are obtained either from the atomic-model or from testing results of synthesized electrode material, selected form the group consisting of electrode composition, Li ion and site concentration in electrode active material, electrode material particles size, electrode material packing density, lithium ion diffusivity in the electrode materials, lithium ion diffusivity in the electrolyte, lithium ion conductivity in the electrode materials, lithium ion conductivity in the electrolyte, and combinations thereof.

6. The method of claim 1, wherein design of the optimization process in the battery-level model of the step 6) and the step 7) comprises:

specifying output parameters for a lithium ion battery with regarding to the battery application requirement, including cell capacity and cell voltage;

specifying input parameters and their levels that are adjusted in the battery-level model and are controlled in a material preparation procedure;

sampling plurality of design combinations in specified design space for the output parameters for each component of the battery-level model with a design of experiment (DOE) approach;

conducting computer simulation of the battery-level models to obtain data sets of the output parameters for all of the design combinations;

identifying an order of importance and an optimal level of the input parameters by evaluating the output parameters derived in the battery-level model;

revising and repeating the optimization steps above if an optimal solution is not found in the above optimization steps.

7. The method of claim 1, wherein the compositional modification of the step 8) is an element doping modification in the atomic-level model realized by steps of:

constructing a lattice unit of an original electrode material with sufficient lattice atoms that make sure a number of dopant element atom be calculated in integer according to a designated doping concentration;

forming a series of revised models by randomly replacing the lattice elements with the dopant atoms according to the doping concentration and a structure symmetry;

calculating system formation energies for each of the revised model;

prioritizing possibilities of the revised doping model by the formation energy and selecting a structure with the lowest formation energy as the doping model for further calculation.

8. The method of claim 7, wherein the doping element for the electrode modification of the step 8) is selected from the group consisting of Na, K, Mg, Al, Ti, V, Cr, Zn, Sr, Sn, Sb, W, Ce, Si, O, F, P, O, and combinations thereof.

9. The method of claim 2, wherein the physical parameters of the synthesized electrode material to be tested for validation of the step 11) comprises material particle size, material conductivity, material elemental composition, and/or lithium ion diffusivity in the material.

10. The method of claim 2, wherein the performance of synthesized electrode material as battery electrode to be tested in the battery cell of the step 13) comprises specific capacity, cell voltage, charging/discharging behavior, cell rate capability, and/or cell capacity fading with charging/discharging cycling.

11. The method of claim 2, further comprising generating a database comprising the factors calculated by the atomic-level model and material physical parameters of basic electrode materials for further modification and optimization.

12. The method of claim 1, wherein a computer program embedded in a non-transitory computer-readable storage medium, when executed by one or more processors, is used for conducting the calculation and the simulation for the electrode material and a battery cell made thereof.

13. A computer-readable medium whose contents cause a computing system to perform the method of claim 1.

14. A computer-readable medium whose contents cause a computing system to perform the method of claim 2.