Electrochemical behavior of pure graphite studied with a powder microelectrode

Abstract

In this work, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques have been used to study the lithiation/delithiation of graphite using powder microelectrode in a 1.2 M LiPF 6 in EC:EMC electrolyte. The advantage of using the powder microelectrode is the possibility to easily study graphite without any additive and determine electrochemical characteristic of Li-insertion. The use of cyclic voltammetry at very low scan rates allows to estimate the diffusion coefficient of lithium inside graphite. The exchange current density of graphite for several state of charge (SoC) has also been determined by EIS measurements. Moreover, the powder microelectrode is a useful tool to study the formation of the solid electrolyte interphase (SEI) on graphite whether by cyclic voltammetry or EIS.

Diffusion-Dependent Graphite Electrode for All-Solid-State Batteries with Extremely High Energy Density

“…To theoretically confirm the electrochemical characteristics of the diffusion-dependent electrodes, four virtual 3D structures of the diffusion-dependent electrodes (2.5, 5, 7.5, and 10 mg/cm 2 ) were formed, and their areal capacities were simulated at 60 °C using the finite element method (Figure a). Details about the simulation conditions are summarized in Figure S12 and Table S1 and S2. − First, it is notable that the simulated areal capacities at 0.1 C-rate are quite similar to the experimental data up to the loading level of 10 mg/cm 2 . However, when the C-rate increases to 0.3C, the loading level of 5 mg/cm 2 is found to be around the maximum level to deliver the theoretical capacity.…”

Matching silicon-based anodes with sulfide-based solid-state electrolytes for Li-ion batteries

“…4ab). In such case, a charge transfer phenomenon does not appear as an RC circuit 39,40 . A clear difference between the two silicon materials shows up already in the pristine state.…”

A Figure of Merit for Fast-Charging Li-ion Battery Materials

“…To demonstrate the effects of diffusion coefficients and geometric sizes, a chart showing the change of FOM with the two factors is shown in Figure . Based on the reported (average) geometric sizes with the corresponding (average) diffusion coefficients (supplementary Table 1), typical characteristic time scales of diffusion were determined to compare the fast-charging capability of different electrode (electrolyte) materials. − The black dashed lines of constant time show corresponding characteristic time scales of diffusion, which divide the battery materials into different regions, considering the geometric (particle size, electrolyte thickness) and chemical (diffusion coefficient) properties.…”