Investigation on diffusion behavior of Li+ in LiFePO4 by capacity intermittent titration technique (CITT)

摘要: Abstract Capacity intermittent titration technique (CITT) was used to investigate the chemical diffusion coefficient ( D ˜ ) of lithium-ion in LiFePO4 cathode material. The values at galvano-charge current 0.2 and 0.4 mA were respectively found range from 8.8 × 10−16 8.9 × 10−14 cm2 s−1 1.2 × 10−16 8.5 × 10−14 cm2 s−1 voltage 3.2 4 V (vs. Li+/Li). transfer coefficients (0.32–0.42) anodic (0.26–0.3), standard rate constant (1.58 × 10−9 1.30 × 10−8 cm s−1) measured Tafel plots equilibrium potential 3.06 3.45 V. From these kinetic parameters, finite kinetics interface taken into account revise above . revised 2.44 × 10−15 2.21 × 10−13 cm2 s−1 5.81 × 10−16 3.22 × 10−13 cm2 s−1 4 V. Results show that approximation infinite charge-transfer leads a spurious value which is lower than value, extent depends on CITT experiment.