Lithium-ion batteries have attracted much interest since widely used in consumer electronics and large scale system such as electric vehicles and smart grids ^[1]. Safety and duration are the most important performance for electrochemical system, to understand the aging mechanism, electrochemical non-destruction analysis differential voltage (DV) and incremental capacity (IC) analysis (dV/dQ and dQ/dV),provided insight into degradation phenomena ^[2].

Commercial 18650s (NCA/Graphite) were chosen to study the aging mechanism. The measured cells capacity was 3018.5mAh at 0.2C at 2.75V to 4.2V at the beginning of life, and 3152.0mAh at 0.01C. After 500 cycles, the 0.2C capacity was 2533.3mAh, and 2939.7mAh at 0.01C. The reversible lithium loss was 212.3mAh, and the resistance increased at the end of life. The fig.2 indicated that the active material was decreased on cycle.

References

[1] M. Armand and J. M. Tarascon, Nature, 451, 652 (2008)

[2] Ira Bloom and Andrew N. Jansen, Journal of Power Sources, 295, 139 (2005)