Graphite is used as a state-of-the-art anode in commercial lithium-ion batteries (LIBs) due to its highly reversible lithium-ion storage capability and low electrode potential. However, graphite anodes exhibit sluggish diffusion kinetics for lithium-ion intercalation/deintercalation, thus limiting the rate capability of commercial LIBs. In order to determine the lithium-ion diffusion coefficient of commercial graphite anodes, we employed a galvanostatic intermittent titration technique (GITT) to quantify the quasi-equilibrium open circuit potential and diffusion coefficient as a function of lithium-ion concentration and potential for a commercial graphite electrode. Three plateaus are observed in the quasi-equilibrium open circuit potential curves, which are indicative of a mixed phase upon lithium-ion intercalation/deintercalation. The obtained diffusion coefficients tend to increase with increasing lithium concentration and exhibit an insignificant difference between charge and discharge conditions. This study reveals that the diffusion coefficient of graphite obtained with the GITT (1 × 10⁻¹¹ cm²/s to 4 × 10⁻¹⁰ cm²/s) is in reasonable agreement with literature values obtained from electrochemical impedance spectroscopy. The GITT is comparatively simple and direct and therefore enables systematic measurements of ion intercalation/deintercalation diffusion coefficients for secondary ion battery materials.

A highly compact and scalable three-dimensional desalination cell was realized by utilizing honeycomb-shaped porous lattice scaffolds.

Flow-electrode-based capacitive deionization (FCDI) is a desalination process that uses electrostatic adsorption and desorption of ions onto electrode materials. It provides a continuous desalination flow with high salt removal performance and low energy consumption. Since lithium has been regarded as an essential element for the last few decades, the efficient production of lithium from the natural environment has been intensively investigated. In this study, we have extracted lithium ions from aqueous solution by using FCDI desalination. We confirmed that lithium and chloride ions could be continuously collected and that the salt removal rate depends on various parameters, including feed-flow rate and a feed saline concentration. We found that the salt removal rate increases as the feed-flow rate decreases and the feed salt concentration increases. Furthermore, the salt removal rate depends on the circulation mode of the feed solution (continuous feed stream vs. batch feed stream), which allows control of the desalination performance (higher capacity vs. higher efficiency) depending on the purpose of the application. The salt removal rate was highest, at 215.06 μmol/m⁻²s⁻¹, at the feed rate of 3 mL/min and the feed concentration of 100 mg/L. We believe that such efficient and continuous extraction of lithium chloride using FCDI desalination can open a new door for the current lithium-production industry, which typically uses natural water evaporation.