Confinement-Controlled Water Engenders Unusually High Electrochemical Capacitance.

The electrodynamics of nanoconfined water have been shown to change dramatically compared to bulk water, opening room for safe electrochemical systems. We demonstrate a nanofluidic "water-only" battery that exploits anomalously high electrolytic properties of pure water at firm confinement. The device consists of a membrane electrode assembly of carbon-based nanomaterials, forming continuously interconnected water-filled nanochannels between the separator and electrodes. The efficiency of the cell in the 1-100 nm pore size range shows a maximum energy density at 3 nm, challenging the region of the current metal-ion batteries. Our results establish the electrodynamic fundamentals of nanoconfined water and pave the way for low-cost and inherently safe energy storage solutions that are much needed in the renewable energy sector.

Growth Features of Bi2Te3Sb1.5 Films on Polyimide Substrates Obtained by Pulsed Laser Deposition.

Thermoelectric materials in the form of thin films are used to create a wide variety of sensors and devices. The efficiency of these devices depends on the quality and efficiency of the thermoelectric materials obtained in the form of thin films. Earlier, we demonstrated that it is possible to obtain high-performance Bi2Te3Sb1.5 films less than 1 µm thick on polyimide substrates by using the PLD method, and determined optimal growth conditions. In the current work, the relationship between growth conditions and droplet fraction on the surface, microstructure, grain size, film thickness and chemical composition was studied. A power factor of 5.25 µW/cm×K2 was achieved with the reduction of droplet fraction on the film surface to 0.57%. The dependencies of the film thickness were studied, and the effect of the thickness on the efficiency of the material is shown. The general trend in the growth dynamics for Bi2Te3Sb1.5 films we obtained is the reduction of crystalline size with Pressure-Temperature (PT) criterion. The results of our work also show the possibility of a significant reduction of droplet phase with simultaneous management of crystalline features and thermoelectric efficiency of Bi2Te3Sb1.5 films grown on polyimide substrates by varying growth conditions.