This perspective provides a new look into how electrolyte structure at the interface controls the kinetics of water reduction.

This is a critical review of artificial intelligence/machine learning (AI/ML) methods applied to battery research. It aims at providing a comprehensive, authoritative, and critical, yet easily understandable, review of general interest to the battery community. It addresses the concepts, approaches, tools, outcomes, and challenges of using AI/ML as an accelerator for the design and optimization of the next generation of batteries─a current hot topic. It intends to create both accessibility of these tools to the chemistry and electrochemical energy sciences communities and completeness in terms of the different battery R&D aspects covered.

Producing hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. With spin-dependent kinetics in OER, to manipulate the spin ordering of ferromagnetic OER catalysts (e.g., by magnetization) can reduce the kinetic barrier. However, most active OER catalysts are not ferromagnetic, which makes the spin manipulation challenging. In this work, we report a strategy with spin pinning effect to make the spins in paramagnetic oxyhydroxides more aligned for higher intrinsic OER activity. The spin pinning effect is established in oxide_FM/oxyhydroxide interface which is realized by a controlled surface reconstruction of ferromagnetic oxides. Under spin pinning, simple magnetization further increases the spin alignment and thus the OER activity, which validates the spin effect in rate-limiting OER step. The spin polarization in OER highly relies on oxyl radicals (O∙) created by 1^st dehydrogenation to reduce the barrier for subsequent O-O coupling.

Aqueous Li-ion batteries have long been envisioned as safe and green energy storage technology, but have never been commercially realized owing to the limited electrochemical stability window of water, which drastically hampers their energy density. Recently, Water-in-Salt electrolytes (WiSEs) in which a large amount of organic salt is dissolved into water were proposed to allow for assembling 3 V Li-ion batteries. Hereby, our attention focused on the fate of water at the electrochemical interface under negative polarization and the potential reactivity of TFSI anions with products originating from the water reduction. Hence, combining analysis of bulk electrolytes with electrochemical measurements on model electrodes and operando characterization, we were able to demonstrate that hydroxides generated during the hydrogen evolution reaction can chemically react with TFSI and catalyze the formation of a fluorinated solid–electrolyte interphase (SEI) that prevents further water reduction. Mastering this new SEI formation path with the chemical degradation of TFSI anions mediated by the electrochemical reduction of water can therefore open new avenues for the future development of not only WiSEs but also Li batteries functioning in organic electrolytes.