A β”‐Alumina/Inorganic Ionic Liquid Dual Electrolyte for Intermediate‐Temperature Sodium–Sulfur Batteries

Abstract

Although sodium-sulfur (Na-S) batteries present the great prospects of high energy density, long cyclability, and sustainability, their deployment is heavily encumbered by safety, practicality, and versatility issues engendered by their high operating temperatures above 300 °C. Lowering the operating temperatures impedes the performance of Na-S batteries due to the formation of insulating S/polysulfides, diminished Na ion conduction in the β"-alumina solid electrolyte (BASE), the Na metal dendrite growth at temperatures below its melting point, and the shuttle effect occurring in the absence of the BASE. Herein, a Na-S battery that integrates a dual electrolyte consisting of the BASE and a novel inorganic ionic liquid is proposed for intermediate-temperature operations of 150 °C. Investigations reveal the ionic liquid to have high ionic conductivity, wide electrochemical window, and excellent thermal and chemical stability, making it propitious for intermediate-temperature operations. The high reversible capacity of 795 mAh (g-S) −1 at 0.1 mA (electrode area: 0.785 cm 2 ) and an average capacity of 381 mAh (g-S) −1 achieved over 1000 cycles at 0.5 mA validate the use of ionic liquids in dual electrolyte systems to improve Na-S performance.

In Situ Orthorhombic to Amorphous Phase Transition of Nb2O5 and Its Temperature Effect on Pseudocapacitive Behavior

“…For instance, the ability to sustain stable operations at intermediate temperatures (above room temperatures) and tolerance to spontaneous temperature fluctuations without compromising safety are expected to become key requisites for future battery applications . However, contemporary commercialized LIBs, which generally utilize carbonate-based organic electrolytes, are known to be unsuitable for elevated-temperature operation because of diminished performance caused by electrolyte degradation and potential fire hazards. − These safety concerns have generated traction among ionic liquid (IL) electrolytes which have been deemed to have high resilience to temperature elevations and fluctuations attributed to their nonflammability and low volatility. ,, Furthermore, intermediate-temperature operations have been found to ameliorate the performance of IL electrolytes, thus creating a new avenue for utilizing the ubiquitous waste heat in daily activities. ,, …”

“…33,37,38 Furthermore, intermediate-temperature operations have been found to ameliorate the performance of IL electrolytes, thus creating a new avenue for utilizing the ubiquitous waste heat in daily activities. 33,39,40 It is evident that pseudocapacitive materials, particularly Nb 2 O 5 , represent an exquisite class of energy materials that promise to revolutionize battery capabilities beyond the contemporary scopes of battery performance. However, studies on the Nb 2 O 5 negative electrode, which typically entail analyses in half-cell configurations in the 1.0−3.0 V cut-off voltage range, are yet to provide a full picture into the electrochemical capability of this material.…”

Interface chemistry for sodium metal anodes/batteries: a review

“…Hence, it is very important to regulate the interface from the composition of electrolytes (salts and solvents) [89] . As shown in Figure 5A, Sun et al designed the first chloroaluminate ionic liquid electrolyte for rechargeable SMBs by adding two important additives (ethylaluminum dichloride and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide) to an ionic liquid consisting of AlCl 3 /1-methyl-3-ethylimidazolium chloride/NaCl [90] . The system exhibited good inflammability and the absence of obvious dendrites.…”

Strategies for Harnessing High Rate and Cycle Performance from Graphite Electrodes in Potassium-Ion Batteries

“…The detrimental effects of organic solvents on battery performance have sparked interest in ionic liquids (ILs) as alternative electrolytes for a variety of battery systems (LIBs, 23 Na-ion batteries (SIBs), 24 Li-S batteries, 25 and Na-S batteries 26 ). This class of electrolytes has been endowed with a trove of exquisite physicochemical properties such as negligible flammability, low volatility, high thermal stability, and wide electrochemical window that facilitate safe operations in a wide temperature range.…”

“…The detrimental effects of organic solvents on battery performance have sparked interest in ionic liquids (ILs) as alternative electrolytes for a variety of battery systems (LIBs, Na-ion batteries (SIBs), Li-S batteries, and Na-S batteries). This class of electrolytes has been endowed with a trove of exquisite physicochemical properties such as negligible flammability, low volatility, high thermal stability, and wide electrochemical window that facilitate safe operations in a wide temperature range. − In addition, several studies have reported remarkable improvements in rate capabilities and cycle life during operations at intermediate temperatures, , thus presenting unique technical and economic prospects of reclaiming ubiquitous waste heat from everyday operations. , Furthermore, several studies have attributed the superior performances observed in ILs to the formation of uniform and robust SEI layers during electrochemical operations. , Among LIBs, a Li­[FSA]-[C 2 C 1 im]­[FSA] (C 2 C 1 im = 1-ethyl-3-methylimidazolium) IL electrolyte was found to have excellent Li metal dendrite suppression capabilities at 25 °C, demonstrating a stable Li deposition/dissolution marked by a consistent overpotential of 12 mV for 1000 h (2500 cycles) at 1 mA cm –2 .…”