仿生与固态能源系统研究组知识库

Flexible pyrolytic polyimide graphite film (PGF) is explored as a cathode current collector in lithium ion batteries using lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) based electrolyte. It is demonstrated that no obvious anodic current is observed up to 4.5 V versus Li+/Li for PGF, while significant corrosion current is found from 3.6 V for aluminum, indicative of better electrochemical stability of PGF than that of aluminum in LiTFSI based electrolyte. LiMn2O4 on aluminum and PGF has been used as model electrode for testing. There is hardly any capacity retained after 10 cycles at room temperature for the LiMn2O4/aluminum electrode. With regard to the LiMn2O4/PGF electrode, the capacity retention ratio remained 89% after 1000 cycles. Moreover, at an elevated temperature of 55 degrees C, the capacity retention ratio kept at 81% after 300 cycles. Since LiTFSI-based electrolyte shows advantages in safety, stability and conductivity but could not be used due to Al-corrosion, the application of the PGF current collector could overcome this barrier. (C) 2014 Elsevier B.V. All rights reserved.