The industrial world needs energy storage devices rather than lithium batteries or double-layer electrochemical capacitors with a specific power and energy density. One of the challenges is to build a durable and safe hybrid supercapacitor with high energy density and specific power and long life. Compared to lithium batteries, the lower heat emission allows the use of simpler, cheaper and more reliable cooling systems. Compared to the existing supercapacitor, the acceleration can be maintained up to 10 times more, due to the higher energy density. Hybrid trucks and buses with frequent starts / stops are also interesting applications where LIC will offer competitive advantages.

The intermittent nature of renewable energies, wind and solar, blocks the growth of these energies or imposes the need for a powerful system of energy storage to operate the electricity network during this short space. LICs are the most competitive tools for bridging the gap between electricity shortages and the actual start-up of generators.

Our team has analyzed the development of electrodes because they are critical because the electrode development process has a considerable impact on the performance of the final device. The best performance cathode was obtained by combining iron phosphate and lithium (LFP) with activated carbon (AC). The choice of electrolyte components is extremely critical to guarantee the performance of the device and in particular the safety. Organic and aquatic electrolytes have been tested to compare the functionality of devices. The experimental results show a synergistic effect between AC (energy storage in double electric layer) and LFP (energy storage by intercalation processes).

References

[1] B. Wang, Q. Wang, B. Xu, T. Liu, D. Wang, RSC Adv, 3 (2013) 20024-20033.

[2] Y. Lei, Z. Huang, W. Shen, F. Kang, Y. Zheng, Electrochimica Acta, 107 (2013) 413-418.

[3] X. Hu, Y. Huai, Z. Lin, J. Sue, Z. Deng, Journal of Electrochemical Society, 154 (2007) A1026-A1030.

Fig: a)Cyclic voltammograms using AC (YP 80F) and LiFePO₄ (0.0 and 20%), reference Li/Li+ electrode, b) Nyquist diagram of AC-LiFePO₄ (diferent potentials),