Prediction of Lithium Diffusion Coefficient and Rate Performance by using the Discharge Curves of LiFePO₄Materials

Abstract

The lithium ion diffusion coefficients of bare, carbon-coated and Cr-doped LiFePO 4 were obtained by fitting the discharge curves of each half cell with Li metal anode. Diffusion losses at discharge curves were acquired with experiment data and fitted to equations. Theoretically fitted equations showed good agreement with experimental results. Moreover, theoretical equations are able to predict lithium diffusion coefficient and discharge curves at various discharge rates. The obtained diffusion coefficients were similar to the true diffusion coefficient of phase transformation electrodes. Lithium ion diffusion is one of main factors that determine voltage drop in a half cell with LiFePO 4 cathode and Li metal anode. The high diffusion coefficient of carbon-coated and Cr-doped LiFePO 4 resulted in better performance at the discharge process. The performance at high discharge rate was improved much as diffusion coefficient increased.

Electronic Property Dependence of Electrochemical Performance for TiO2/CNT Core-shell Nanofibers in Lithium Ion Batteries

“…Yet at room temperature the amount of lithium that can be intercalated into bulk rutile is negligible due to the stringent structure and highly anisotropic 1-D lithium diffusion channel [19,22,23]. Instead, anatase is considered most appropriate as lithium insertion hosts [24][25][26].…”

“…Various delicate structures, such as nanoparticles, nanowires and mesoporous structures were fabricated to attain larger practical capacity [34,35]. Alternative means to improve the capacity via enhancing the materials' electronic properties [23,[36][37][38], such as carbon loading, metal oxides doping, i.e. ZnO, SnO 2 , RuO 2 , etc., and forming composite with silicon, were also attempted [39][40][41][42][43][44].…”

Determining the electrochemical transport parameters of sodium-ions in hard carbon composite electrodes

“…EIS is mainly used to investigate the diffusion in cathode materials as the crystal structure changes during charge and discharge. [58,60,[71][72][73][74] It should be noted that the resolution within the low voltage region is very low when conducting staircase PEIS. Additionally, the data acquisition is not as accurate within the low voltage plateaus.…”