Association and Diffusion of Li+ in Carboxymethylcellulose Solutions for Environmentally Friendly Li‐ion Batteries

Abstract Carboxymethylcellulose (CMC) has been proposed as a polymeric binder for electrodes in environmentally friendly Li‐ion batteries. Its physical properties and interaction with Li + ions in water are interesting not only from the point of view of electrode preparation—processability in water is one of the main reasons for its environmental friendliness—but also for its possible application in aqueous Li‐ion batteries. We combine molecular dynamics simulations and variable‐time pulsed field gradient spin‐echo (PFGSE) NMR spectroscopy to investigate Li + transport in CMC‐based solutions. Both the simulations and experimental results show that, at concentrations at which Li‐CMC has a gel‐like consistency, the Li + diffusion coefficient is still very close to that in water. These Li + ions interact preferentially with the carboxylate groups of CMC, giving rise to a rich variety of coordination patterns. However, the diffusion of Li + in these systems is essentially unrestricted, with a fast, nanosecond‐scale exchange of the ions between CMC and the aqueous environment.