Acid-in-clay electrolyte for wide-temperature-range and long-cycle proton batteries

Proton conduction underlies many important electrochemical technologies. We report a series of new proton electrolytes: acid-in-clay electrolyte termed AiCE, prepared by integrating fast proton carriers in a natural phyllosilicate clay network, that can be made into thin-film (tens of microns) fluid-impervious membranes. The chosen example systems (sepiolite-phosphoric acid) rank top among the solid proton conductors in consideration of proton conductivities (15 mS cm−1 at 25 °C, 0.023 mS cm−1 at −82 °C), the stability window (3.35 V), and reduced chemical activity. A solid-state proton battery was assembled using AiCE as the electrolyte to demonstrate the performance of these electrolytes. Benefitting from the wider electrochemical stability window, reduced corrosivity, and excellent ionic selectivity of AiCE, the two main problems (gasification and cyclability) of proton batteries have been successfully solved. This work also draws the attention of elemental cross-over in proton batteries and illustrates a simple “acid-in-clay” approach to synthesize a series of solid proton electrolytes with a superfast proton permeability, outstanding selectivity, and improved stability for many potential applications associated with protons.

Non-Polar Lipids as Regulators of Membrane Properties in Archaeal Lipid Bilayer Mimics

The modification of archaeal lipid bilayer properties by the insertion of apolar molecules in the lipid bilayer midplane has been proposed to support cell membrane adaptation to extreme environmental conditions of temperature and hydrostatic pressure. In this work, we characterize the insertion effects of the apolar polyisoprenoid squalane on the permeability and fluidity of archaeal model membrane bilayers, composed of lipid analogues. We have monitored large molecule and proton permeability and Laurdan generalized polarization from lipid vesicles as a function of temperature and hydrostatic pressure. Even at low concentration, squalane (1 mol%) is able to enhance solute permeation by increasing membrane fluidity, but at the same time, to decrease proton permeability of the lipid bilayer. The squalane physicochemical impact on membrane properties are congruent with a possible role of apolar intercalants on the adaptation of Archaea to extreme conditions. In addition, such intercalant might be used to cheaply create or modify chemically resistant liposomes (archeaosomes) for drug delivery.