As the world into the era of 3G/4G, 3G/4G phones and netbooks gradually popular, mobile Internet, games, video more extensive application of all these applications need to be on the phone for a long time operation, the need of mobile phone battery can support a long time, it puts forward higher requirements on lithium ion batteries, thus to improve the specific energy of lithium ion battery has become one of the problems to be solved^1-2. At present mainly in order to improve the specific energy of lithium ion battery by boosting voltage of LiCoO₂ material, while it will also bring adverse effect to LiCoO₂ materials. So it is necessary to study the evolution of the LiCoO₂under high voltage cycling.

In this paper, we used the three electrodes to monitor the potential changes of LiCoO₂ and graphite from the battery initial state charged to 4.5 V (as shown in figure 1), and before and after cycling. Study the morphology, structure and surface changes of LiCoO₂before and after cycling under 4.5V high voltage by using differential capacitance, scanning electron microscopy, X-Ray Diffraction (as shown in figure 2), Raman, IR and differential scanning calorimetry analysis characterization methods.

Acknowledgements

The project was supported by the Shanghai Science and Technology Development Fund (15DZ2282000) and (14JC1491800)

References

[1]. A. Aboulaich*, K. Ouzaouit, H. Faqir, A. Kaddami, I. Benzakour, I. Akalay. Materials Research Bulletin 73 (2016) 362-368.

[2]. Y. Ito, Y. Sakurai, S. Yubuchi, A. Sakuda, A. Hayashi^∗,and M. Tatsumisago, J. Electrochem. Society, 162 (8) (2015) A1610-A1616.