Studies Of The Rate Capability Of Composite Electrode Of Capacitor Carbon And Ternary Materials Or Lithium Iron Phosphate

With the increasingly severe energy crisis and environmental crisis,electric vehicles become the future direction of the development of the automobile industry.However,key factors of battery technology constraints,especially the rapid charging performance of the battery need to be improved,hinder the development of electric vehicle industry.In this paper,NCA/capacitor carbon,NCM/capacitor carbon and LFP/capacitor carbon Composite electrodes were prepared by using capacitive carbon and commercial lithium iron phosphate(LFP),nickel cobalt aluminum ternary material(NCA)and nickel cobalt manganese ternary material(NCM),to improve their high rate performance of the charge and discharge.The effects of AC1,AC2,AC3 and AC4 on the commercial NCA rate performance were studied.The results showed when AC1,AC2,AC3 and AC4 were added for 3%,8%,5% and 5% at the loading of active substances at 4 mg/cm2,the rate performance of NCA is maximized.Which is the largest increase in NCA rate performance is when 3%AC1 capacitor carbon was added,and its charge and discharge capacity of 5 C charge-5 C discharge,10 C charge-10 C discharge and20 C charge-20 C discharge is reach up to 116,102 and 85 m Ahg-1,respectively,however,only 52,43 and 18 m Ahg-1 for blank NCA electrode.Adding 3%AC1 capacitor carbon can improve the performance of commercial NCA cathode materials at high temperature.The composite electrode of adding 3%AC1 capacitor carbon can discharge 129 m Ahg-1 after 100 cycles in the constant temperature of 55?,at 1 C rate of charge and discharge,which the capacity retention rate is 92.85%,while the blank NCA cathode material can discharge 115 m Ahg-1,which the capacity retention rate is 72.32% in the same conditions.The effects of AC1,AC2,AC3 and AC4 on the commercial NCM rate performance were studied.The results showed when AC1,AC2,AC3 and AC4 were added for 3% at the loading of active substances at 4 mg/cm2,the rate performance of NCM at 5C and 10 C is improved to small extent and barely at 20 C.The rate performance of the NCM material can not be improved continuing to increase the content of carbon.Which is the largest increase in NCM rate performance is when3%AC3 capacitor carbon was added,and its charge and discharge capacity of 5 C charge-5 C discharge,10 C charge-10 C discharge and 20 C charge-20 C discharge is reach up to 85,62 and 28 mAhg-1,while only 62,48 and 26 mAhg-1 for the blank NCM electrode.The effects of AC1,AC2,AC3 and AC4 on the commercial LFP rate performance were studied.The results showed when AC1,AC2,AC3 and AC4 were added for 8%,8%,3% and 8% at the loading of active substances at 4 mg/cm2,the rate performance of LFP is maximized.Among them,when 8%AC1 capacitor carbon was added,the LFP rate performance is the largest increase,and its charge and discharge capacity of 5 C charge-5 C discharge,10 C charge-10 C discharge and 20 C charge-20 C discharge is reach up to 102,85 and 63 m Ahg-1,however,only 77,8 and 1m Ahg-1 for blank LFP electrode.The above studies show that the capacitor carbon can effectively improve the rate performance of lithium-ion battery cathode materials,and the technology of direct mechanical mixing process is simple and easy to industrial applications.