QIBEBT Develops High Performance Carbon-based Materials and Their Application in Energy Storage Devices
The low-speed electric vehicle industry has been rapidly developing globally due to their advantages in low prices, convenient charge/discharge, and etc.. However, the application of lead-acid batteries in low-speed electric vehicles, which can cause environmental pollution, limits its further development in certain extent.
As green and efficient energy storage devices, it is required that the energy density of lithium ion capacitors (LICs) is as high as 30 Wh/kg. LICs are promising substitutes for lead-acid batteries. The Advanced Energy Storage Technology Center of Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT), Chinese Academy of Sciences, has developed high performance LICs devices and solved a series of key technology, such as predoping lithium process. After 1500 cycles, the capacity retention of the LICs is above 93%.
In order to make the graphite more valuable, the research center has developed key electrode materials for LICs (J. Mater. Chem., 2012, 22: 24918; J. Mater. Chem. A, 2013, 1: 5949) and electrocatalytic materials for vanadium redox flow batteries (VRFBs) by using graphene materials. Based on the previous studies in high efficient graphene materials for vanadium ion redox reactions (Carbon, 2011, 49: 693; Energy Environ. Sci., 2011, 4: 4710), the scientists have also synthesized the RuSe/reduced graphene oxide composite materials for VO2+/VO2+ redox couples in VRFBs (RSC Adv., 2014, 4: 20379).
QIBEBT researchers explored the flexible pyrolytic polyimide graphite film (PGF) as a cathode current collector in lithium ion batteries (LIBs) using lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) based electrolyte. PGF possesses a highly in-plane oriented structure, which endows it with excellent electrochemical corrosion resistance and exhibits much better electrochemical stability than aluminum current collectors in LiTFSI based electrolyte. The result demonstrated that no obvious anodic current occurred up to 4.5 V versus Li+/Li for PGF, while significant corrosion current was found from 3.6 V for aluminum. This indicates that, in LiTFSI based electrolyte, PGF has better electrochemical stability than aluminum does.
Furthermore, scientists tested LiMn2O4 on PGF and aluminum as a model electrode, respectively. With regard to the LiMn2O4/PGF electrode, the capacity retention ratio remained 89% after 1000 cycles. And at an elevated temperature of 55oC, the capacity retention ratio kept at 81% after 300 cycles. However, for the LiMn2O4/aluminum electrode, there is hardly any capacity retained after 10 cycles at room temperature (Electrochem. Commun., 2014, DOI: 10.1016/j.elecom.2014.05.001).
The research work is led by professor CUI Guanglei at QIBEBT and under the support of the National 863 Project and the Key Technology Research Projects of Qingdao, China.
References:
(1) Journal of Materials Chemistry, 2012, 22(47): 24918-24923
(2) Journal of Materials Chemistry A, 2013, 1: 5949-5954
(3) Electrochemistry Communications, 2014, DOI: 10.1016/j.elecom.2014.05.001
(4) RSC Advances, 2014, 4 (39), 20379- 20381
Contact:
Prof. CUI Guanglei
Email: cuigl (AT) qibebt.ac.cn
