High-Temperature Preconditioning Reduces Lithium Plating in LG Chem HG2 18650 Cells at -20°C
Preconditioning LG Chem HG2 cells at 30°C before -20°C cycling reduces Li plating via microstructural changes detectable by CT and 3D modeling. The arXiv preprint demonstrates protocol-specific mitigation of low-temperature degradation. Evidence is limited to one cell chemistry and short-term tests.
The study tested three protocols on commercial 18650 cells: two weeks of galvanostatic cycling at 30°C, two weeks of storage at 30°C, and immediate transfer to -20°C cycling without preconditioning. Researchers combined X-ray computed tomography of electrode microstructure with spatially resolved 3D electrochemical modeling to trace how prior high-temperature exposure altered porosity, SEI growth, and local current distribution that drive plating.
Preconditioned cells exhibited visibly less dendritic Li deposits and slower capacity fade during low-temperature operation. Modeling indicated that 30°C preconditioning increased average pore connectivity and reduced overpotentials at the anode, shifting the onset of plating to higher charge rates. These effects were absent in the reference group, confirming protocol dependence rather than simple temperature history.
For spacecraft using COTS cells, the approach offers a low-cost operational safeguard against irreversible degradation and safety risks below 0°C. Terrestrial implications include potential adaptation for EV fleets in arctic conditions, though the single-cell-type design and limited cycle counts leave scalability unproven. Larger multi-cell packs with varied electrolytes would strengthen evidence for broader adoption.
Lehnert: Follow-up 200-cycle tests will show preconditioned cells retain at least 12% more capacity than controls at -20°C by December 2026.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2609.25005)
- [2]Supporting Source(https://doi.org/10.1016/j.jpowsour.2023.233456)