Spurious potential dependence of diffusion coefficients in Li+ insertion electrodes measured with PITT

摘要: Abstract Diffusion coefficients of Li+ in insertion electrodes determined by the potentiostatic intermittent titration technique (PITT) have been reported literature as being potential-dependent (and thus dependent on degree insertion). With this PITT method diffusion DPITT are from current response potential-step experiments using an approach based Cottrell equation. This equation assumes boundary conditions infinitely fast kinetics and a linear system with semi-infinite thickness. Using example spinel-type LiδMn2O4 electrode it will be demonstrated that potential dependence is not real but occurs, because inadmissible condition which fulfilled has adopted. help numerically simulated data calculated constant coefficient D. these dependent, even though were The thickness applied to bed spherical active particles finite radii represented leads further deviations investigated.