Among the applications for protic ionic liquids (PILs), lubrication is one of the newest and the most promising. In this work, ammonium-based protic ionic liquids were tested as lubricant fluids for aluminum-steel contacts. PILs were synthesized with 2-hydroxyethylamine (2HEA) and a carboxylic acid (formic and pentanoic), aiming to understand the effect of two different anion chain lengths on the lubricant behavior. The synthesized PILs were characterized by RMN, FTIR and TGA. Wear tests, conducted using a ball-on-plate configuration, showed that the increase of the anion carbon chain length in the PIL structure reduced significantly the coefficient of friction value. Besides, after the wear tests, the PILs structural integrity was not affected. In the same way, bending under tension (BUT) tests evidenced that the performance for stamping conditions of the PIL with the longest anion carbon chain was similar to that of the commercial lubricant. Since, both formed a uniform tribofilm, developed the same lubrication regime and the drawing forces values were close and constant. Hence, the ionic liquid obtained with 2HEA and pentanoic acid (2HEAPe) is as suitable as the commercial lubricant for metal forming processes.

Switchable supercapacitors (SCs) enable a reversible electrically‐driven uptake/release of bioactive ions by polarizing porous carbon electrodes. Herein we demonstrate the first example of a bioactive ion‐based switchable supercapacitor. Based on choline chloride and porous carbons we unravel the mechanism of physisorption vs. electrosorption by nuclear magnetic resonance, Raman, and impedance spectroscopy. Weak physisorption facilitates electrically‐driven electrolyte depletion enabling the controllable uptake/release of electrolyte ions. A new 4‐terminal device is proposed, with a main capacitor and a detective capacitor for monitoring bioactive ion adsorption in situ. Ion‐concentration control in printed choline‐based switchable SCs realizes switching down to 8.3 % residual capacitance. The exploration of adsorption mechanisms in printable microdevices will open an avenue of manipulating bioactive ions for the application of drug delivery, neuromodulation, or neuromorphic devices.

Capacitive analogues of semiconductor diodes (CAPodes) present a new avenue for energy‐efficient and nature‐inspired next‐generation computing devices. Here, we disclose the generalized concept for bias‐direction‐adjustable n‐ and p‐CAPodes based on selective ion sieving. Controllable‐unidirectional ion flux is realized by blocking electrolyte ions from entering sub‐nanometer pores. The resulting CAPodes exhibit charge‐storage characteristics with a high rectification ratio (96.29 %). The enhancement of capacitance is attributed to the high surface area and porosity of an omnisorbing carbon as counter electrode. Furthermore, we demonstrate the use of an integrated device in a logic gate circuit architecture to implement logic operations (‘OR’, ‘AND’). This work demonstrates CAPodes as a generalized concept to achieve p‐n and n‐p analogue junctions based on selective ion electrosorption, provides a comprehensive understanding and highlights applications of ion‐based diodes in ionologic architectures.