Sodium and potassium ion rich ferroelectric solid electrolytes for traditional and electrode-less structural batteries

Abstract

The transition to a sustainable society is vital and requires electrification. Sodium and potassium ion-based electrolytes will likely play an important role in energy storage as these elements are very abundant. The latter cations and chloride are especially interesting since life on the planet is somehow based on biological transfers of these ions through cell membranes. K+ is the key charge carrier in plants. Here, we characterize electrochemically, electrostatically, and structurally novel electrolytes, K3ClO and K2.99Ba0.005ClO, and compare their performance with Na3ClO and Na2.99Ba0.005ClO in symmetric and asymmetric structural electrode-less cells, such as K/K2.99Ba0.005ClO in a cellulose membrane/K, Na/Na2.99Ba0.005ClO in a cellulose membrane/Na, Al/K2.99Ba0.005ClO composite/Cu, and Al/Na2.99Ba0.005ClO composite/Cu, at temperatures that range from −45 to 65 °C. An ab initio molecular dynamics structural study followed by band structure determination using density functional theory and hybrid simulations allowed us to compare the amorphous character of the structures, bandgap, and electron localization function for both K3ClO at 25 °C and Na3ClO at 37 °C, temperatures at which preliminary studies indicate that these compounds are already amorphous. As in Na+-based electrolytes, the ferroelectric character of the K+-based electrolytes is well recognizable, especially at −45 °C, where the relative real permittivity achieves 1013 in K/K2.99Ba0.005ClO in cellulose membrane/K symmetric cells for an ionic conductivity of ∼120 mS/cm. As in Na+-based electrodes-less structural battery cells, self-charge and self-cycling phenomena are also demonstrated reinforcing the ferroelectric nature of the A3ClO (A = Li, Na, and K) family of electrolytes. These studies may contribute to understanding the K+ and Na+ transfer behavior in energy harvesting and storage as well as the biologic world.

Giant Polarization in Quasi‐Adiabatic Ferroelectric Na+ Electrolyte for Solid‐State Energy Harvesting and Storage

“…After obtaining the dry Na 2.99 Ba 0.005 ClO solid‐state material, the electrolyte was ground for 40 min (300 rpm) using a ball milling machine with an Agate container and five balls with a diameter of 20 mm, which can be closed hermetically to avoid water absorption during the process. [ 17 ]…”

“…The quasi‐adiabatic ferroelectric discussed herein, shows features of all the three previous regions, not being fully identified with any of them. The properties shown remit to a PNR ferroelectric relaxor with 1D chains [ 17 ] that preserve the long‐range polarization order leading to an extremely high P r while not conducing to dissipative effects under the action of a variable applied electric field, as the chains’ ends polarization is easily altered.…”

“…[15] Herein, we show that Na 2.99 Ba 0.005 ClO glass-electrolyte belongs to the family of relaxor-ferroelectric oxides with low resistance (high ionic conductivity), self-charge (negative resistance) [16] , and selfcycling behavior. [8,17] The electrolyte's thermal behavior and thermodynamic, ionic, and electrical properties are multi-coupling features, affecting different parameters related to the battery, such as safety, cycle life, and electrochemical reactions. [18][19][20] Investigation of the thermal behavior of the electrolyte is crucial to improve its performance within the cell.…”

Interfacial Chemistry with ZnO: In Operando Work Functions in Heterocells

“…Local density (LDA) and generalized gradient approximations (GGAs) underestimate the band gap E g , significantly, which translates into difficulty in calculating the absolute positions of the defect and donor levels relative to the valence or conduction band edges . As highlighted in ref , the hybrid functional HSE06 is more suitable for simulating the electric properties of semiconductors such as ZnO. Here, we have optimized the wurtzite structure of ZnO, the hexagonal P6 3 mc space group, using DFT, and the electrical properties (including band structure) and optical properties using DFT and HSE06.…”

“…Lithium ion is the most desired mobile ion as lithiated anodes and cathodes allow higher energy density. However, lithium is not widely available, 2 and in both brine and mineral formulations, environmental challenges arise in extraction and refinement processes.…”