Effect of an acetylene black film on the performance of commercial lithium iron phosphate

BAI Ying; LI Mengjiao; ZHAO Mian; LIANG Xiaoxuan; LI Weijia; WANG Hui; DING Keqiang

doi:10.19996/j.cnki.ChinBatlnd.2025.05.005

Abstract：As compared to the ternary cathode materials of lithium ions batteries(LIBs),the advantages of relatively stable structure and low risk of safety accident endowed lithium iron phosphate(LiFePO4,abbreviated as LFP)a wide application in the field of LIBs.How to further develop the electrochemical performance of LFP has become a hot topic in the research field of LIBs.In the present work,a physical coating method was used to apply acetylene black on the surface of the commercial current collector of aluminum foil forming a novel kind of current collector.Subsequently,the as-prepared current collector was used to prepare LFP electrode generating an acetylene black membrane coated Al foil supported LFP electrode.It was revealed that the initial discharge capacity of the newly prepared LFP was as high as 217 mAh/g,significantly higher than that of the conventional LFP electrode(165 mAh/g).The discharge capacity of the new LFP electrode at 10 C after 100 cycles was 76 mAh/g,showing an increase of about 30%compared to that of the conventional LFP electrode(58 mAh/g).At 20 C after 500 cycles,the discharge capacity of the new LFP electrode was still as high as 38 mAh/g,presenting an increase of about 40%compared to that of the conventional LFP electrode(27 mAh/g).In this work,the techniques of galvanostatic charge-discharge(GCD),cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS)were all employed to systematically study the electrochemical performance of the studied electrodes.And,XRD(X-ray diffraction),SEM(scanning electron microscopy)and FTIR(Fourier transform infrared spectroscopy)were used to characterize the studied samples before and after the high rate long-term experiments.The greatly reduced charge transfer resistance of LFP electrode as well as the evidently inhibited corrosion process of Al foil was analyzed to be the main contributions of the newly formed acetylene black membrane providing LFP a satisfactory high rate performance.The feature of easy large-scale commercial production made the present work very meaningful to the further development of the LFP-based LIBs.