Welcome to “Week 2” of battery materials simulation series using Materials Square! In this lab, we take a deeper dive into lithium ion dynamics—an essential process for understanding battery performance.
Lab.2 Topic: Li Diffusion Activation Barrier in Bulk LiFePO₄
Understanding how lithium ions move inside a battery material is key to improving charge rates and efficiency. In this simulation, we calculate the activation barrier for lithium diffusion between two adjacent Li sites in a bulk LiFePO₄ structure using the NEB (Nudged Elastic Band) method.
Learning Objectives
Model a bulk structure with Li vacancy sites (initial and final states)
Use NEB simulations to map the Li migration pathway
Analyze the energy barrier to determine the rate-limiting step of diffusion
Simulation Workflow
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Build the Model
Set up the bulk crystal structure of LiFePO₄ and remove Li atoms to create initial and final vacancy sites for diffusion.
(See Structure Builder image – Page 5–6 of curriculum) -
Run NEB Calculation
Use the QE NEB module on Materials Square to simulate intermediate states. The default setup includes 9 NEB images with climbing image optimization.
(See NEB input panel – Page 7) -
Interpret Results
Visualize the energy profile of the Li ion migrating between sites. The energy peak represents the activation barrier, which is critical for evaluating material conductivity.
(See energy profile graph – Page 8)
- Estimated cost: $3 at materials square
- Material: LiFePO₄ (bulk)
- Tool: Quantum ESPRESSO on Materials Square
Next week, we’ll move to the surface:
[Lab.3] Adsorption Energies of Li Atoms at Various Coverage Levels
Let us know if you’d like the input files or project workspace for your own simulation practice. Collaboration is welcome!
Download Material Here : https://drive.google.com/file/d/109eDfWeE8TBGo_wkRA1M_jofkEHPBCX2/view?usp=sharing