I have measured charge-discharge capacity at 0.2 of pure Li4Ti5O12 (LTO) and modified LTO (LTO-N) as shown in the attached Figure. I both the cases, the discharge capacity is higher than charge capacity. The theoretical 175 mAh/g
Qcharge/Qdischarge for pure LTO ~ 0.99
Qcharge/Qdischarge for pure LTO ~0.98
Why discharge capacity is higher than discharge capacity?
How to calculate Coulambic efficiency?