Electrochemical kinetics study of Li-ion in Cu6Sn5 electrode of lithium batteries by PITT and EIS

The kinetics of Li-ion intercalation/alloying into Cu6Sn5 electrode was determined by potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS) method. Although the Li-ion diffusion coefficient (DLi) values are relatively high (from 10−11 to 10−10 cm2/s) in the most voltage range, two minima (below 10−11 cm2/s) in the DLi vs. voltage curve were observed at ∼0.4 and 0.1 V, coinciding with the voltage plateau in the charge/discharge curves, indicating reversible structural phase transition or order/disorder transition in the compound. The DLi derived from PITT and EIS were confirmed well both in the magnitudes and in the variation within Li composition (voltage) range.