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Coulombic efficiency is a key parameter in evaluating the performance and lifespan of batteries. It measures how effectively a battery converts charge during charging and discharging cycles. Higher efficiency indicates less energy loss and better battery health over time.
What Is Coulombic Efficiency?
Coulombic efficiency, often expressed as a percentage, compares the total charge extracted from a battery to the charge supplied during charging. It is calculated by dividing the discharge capacity by the charge capacity and multiplying by 100.
Calculating Coulombic Efficiency
The formula for Coulombic efficiency (CE) is:
CE (%) = (Discharge Capacity / Charge Capacity) × 100
For example, if a battery charges with 1000 mAh and discharges with 990 mAh, the efficiency is:
CE = (990 / 1000) × 100 = 99%
Implications for Battery Longevity
Higher Coulombic efficiency indicates less energy loss during cycling, which can extend the battery’s lifespan. Conversely, lower efficiency suggests energy losses due to side reactions or degradation processes, leading to faster capacity fade.
Factors Affecting Coulombic Efficiency
- Electrode material stability
- Electrolyte composition
- Charging and discharging rates
- Temperature conditions