(6jo) Layered Double Hydroxides as Anion Intercalation Electrodes for Battery-Inspired Water Desalination

Layered double hydroxides (LDHs) are a class of inorganic anion exchange materials with atomic structures similar to naturally occurring clays. Here we study LDH nanoparticles as a model for electrochemically cycleable anion intercalation materials. This work aims to build a fundamental basis for understanding anion intercalation electrochemistry in LDHs through a combined experimental and computation approach to provide direction to the development of cheaper, more efficient, and longer-lifetime materials for anion extraction in battery-inspired water desalination.

LDH nanoparticles are synthesized by coprecipitation followed by hydrothermal treatment, and studied electrochemically in electrolytes containing halide anions. Equilibrium potentials for anion insertion/extraction in the LDH are evaluated theoretically using ab initio quantum mechanical calculations. The combination of these experimental and theoretical techniques provides a mechanistic picture for anion intercalation based on the electronic properties of the anion host material. Future work will focus on experimentally observing insertion and extraction of anions in the LDH nanoparticles during electrochemical cycling using in situ high energy X-ray diffraction (HE-XRD) and X-ray absorption fine-structure spectroscopy (XAFS).