A Membrane-Free and Energy-Efficient Three-Step Chlor-Alkali Electrolysis with Higher-Purity NaOH Production

Parallel Paired Photoelectrochemical Bromination of Alkylarenes with Electrochemical Pinacol Coupling

A paired electrochemical method for paralleling benzylic bromination of alkylarenes under irradiation with reductive pinacol coupling in a divided cell has been developed. A variety of benzyl bromides at the anode and pinacols at the cathode were obtained simultaneously in moderate-to-high faradaic efficiency. This parallel paired electrochemical protocol showed a broad substrate scope and high chemoselectivity as well as high synthetic and faradaic efficiencies.

Modeling and Validation of a LiOH Production Process by Bipolar Membrane Electrodialysis from Concentrated LiCl

Electromembrane processes for LiOH production from lithium brines obtained from solar evaporation ponds in production processes of the Salar de Atacama are considered. In order to analyze high concentrations' effect on ion exchange membranes, the use of concentrated LiCl aqueous solutions in a bipolar membrane electrodialysis process to produce LiOH solutions higher than 3.0% by mass is initially investigated. For this purpose, a mathematical model based on the Nernst-Planck equation is developed and validated, and a parametric study is simulated considering as input variables electrolyte concentrations, applied current density, stack design, process design and membrane characteristics. As a novelty, this mathematical model allows estimating LiOH production in a wide concentration range of LiCl, HCl and LiOH solutions and its effect on the process, providing data on final LiOH solution purity, current efficiency, specific electricity consumption and membrane performance. Among the main results, a concentration of 4.0% to 4.5% by LiOH mass is achieved, with a solution purity higher than 95% by mass and specific electrical energy consumption close to 4.0 kWh/kg. The work performed provides key information on process sensitivity to operating conditions and process design characteristics. These results serve as a guide in the application of this technology to lithium hydroxide production.

Efficient and Facile Electrochemical Process for the Production of High-Quality Lithium Hexafluorophosphate Electrolyte

The global consumption for lithium hexafluorophosphate (LiPF₆) has increased dramatically with the rapid growth of Li-ion batteries (LIBs) for large-scale electric energy storage applications. Conventional LiPF₆ production has a high cost and high energy consumption due to complicated separation and purification processes. Here, based on the electrode materials of LiMn₂O₄ and polyaniline (PANI), we propose a facile electrochemical extraction/release process for LiPF₆ electrolyte production. This new technology consists of two independent steps: a PF₆^-- and Li⁺-extracting step using a PANI/Li_xMn₂O₄ cell in aqueous solution (an ion extraction step) and a LiPF₆ electrolyte production step from the charged LiMn₂O₄/PANI⁺PF₆^- cell in an organic electrolyte (an ion release step). This new process can effectively avoid the contamination of HF residue in the final product, providing a great possibility to create a facile, energy-efficient, and low-cost LiPF₆ electrolyte production.