High-rate Performance of Binder-Free LiFePO4 Cathode Prepared by Using Various Types of Conductive Carbons

A series of binder-free LiFePO4 cathode discs prepared by dry-pressing the mixture of LiFePO4 and various con-ductive carbon. Among those cathode discs, the cathode disc with thickness of 70 mu m, prepared at the pressure of 334 MPa and composed of LiFePO4 and layered holey graphene (CDLL-70 disc) exhibits the best electro-chemical performance in the electrolyte of 1.0 mol L-1 lithium bis(trifluoromethanesulphonyl)imide and 0.1 mol/L LiNO3 in ethylene glycol dimethyl ether:dioxolane in 1:1 wt%. LiFePO4 in the CDLL-70 disc exhibits the stable olivine structure (Space group: Pmnb, JCPDS 40-1499) after charge-discharged for 100 cycles. The CDLL-70 disc exhibits excellent electrical contact between LHG matrix and LiFePO4 particles for homogeneous structure. The CDLL-70 disc exhibits the discharge capacity of 111.7 mAh cm-3 (138.2 mAh g-1) (1st cycle) and 111.2 mAh cm-3 (137.5 mAh g-1) (150th cycle), respectively. The capacity retention rate of the CDLL-70 disc in 150 cycles is 99.5 %. Therefore, the CDLL-70 disc exhibits the excellent rate performance and cycle sta-bility for its excellent flexibility.