Differential Capacity Quantification of Non Reversible Plated Metallic Lithium Microstructures
Differential capacity sweeps at C/20 isolate non reversible plated lithium by separating reversible stripping peaks from active lithium inventory loss.
Pseudo Open Circuit Voltage
Meaning
Thermodynamic equilibrium potential measurements obtained by cycling a cell at an extremely low current rate provide a continuous reference curve. Applying a tiny current reduces the overpotential to negligible levels, meaning that this pseudo open circuit voltage is close to the true thermodynamic value. This continuous measurement is much faster than waiting for the battery to rest at separate states of charge.
Measurement Technique
Low current rates of approximately C over twenty are applied to the cell during charge and discharge. This pseudo open circuit voltage curve is then calculated by averaging the charging and discharging profiles to cancel out the remaining ohmic resistance. The resulting line is used as a reference to calibrate state of charge algorithms.
Electrochemical Analysis
Differential capacity profiles generated from these low-rate curves show distinct peaks that correspond to phase transitions in the anode and cathode. This pseudo open circuit voltage analysis helps researchers identify the degradation of specific active materials without destroying the cell. Changes in the peak heights indicate loss of active material or loss of lithium inventory.
Process Limitation
Total test duration remains a bottleneck in manufacturing lines where high throughput is required. Running a single test takes forty hours of machine time, restricting the technique to laboratory and quality audit roles.