Dry Pouch Cells with NCM811 +Si/C for Lithium-Ion Battery, 1 Ah/pcs/pack, CLIBDPCNCM811SiC

Assembling Dry Pouch Cells using NCM811 (LiNi0.8Co0.1Mn0.1O2) and Silicon-Carbon (Si/C) composites represents a high-energy-density "dream team" for Lithium-ion research. This configuration targets the 300-350 Wh/kg range, but it is notoriously difficult to manage due to the chemical and mechanical instability of both materials. The "Dry" stage is an absolute necessity here to perform extreme dehydration and to establish a baseline for the mechanical stress the cell will face once the silicon begins to expand.

For this chemistry, the dry assembly serves as the ultimate "clean room" gate: (1) Eliminating Lattice Moisture: NCM811 is extremely hygroscopic. Any moisture trapped in the "Dry" cell will react with LiPF6 (once injected) to form HF acid, which attacks the NCM surface and leaches transition metals. (2) Mechanical Baseline: Because Silicon expansion is so aggressive, the "Dry" cell allows you to measure the initial thickness and stack pressure of the cell before any cycling occurs. (3) Si/C Degassing: Silicon-carbon composites often have high internal porosity. Vacuum-sealing the dry pouch ensures that all air is removed from the anode pores, preventing "dry spots" where the electrolyte fails to penetrate.

Testing Processes:

(1) Electrolyte Filling with recommended amount in glovebox.
(2) First Time Aging: 45°C, aging time ≥ 15h in an oven.
(3) Formation conditions: 45°C, 5 min rest; 0.02C constant current charging (10% theoretical capacity or 5 h); 0.1C constant current charging (30% theoretical capacity, 3 h); 5 min rest; total capacity is 40% or 8 h;
(4) Second Time Aging: 45°C, aging time ≥ 24h in a oven
(5) Battery Analyzer for charging and discharging.

References:

1. Z. Deng, et al., Ultrasonic Scanning to Observe Wetting and “Unwetting” in Li-Ion Pouch Cells, Joule, 2022, 4, 2017-2029. 
2. C. P. Aiken, et al., An Apparatus for the Study of In Situ Gas Evolution in Li-Ion Pouch Cells, J. Electrochem. Soc., 2014, 161, A1548.