Stable Cycling of Room‐Temperature Sodium‐Sulfur Batteries Based on an In Situ Crosslinked Gel Polymer Electrolyte

Abstract

High-temperature sodium-sulfur battery (HT Na-S) technology has attracted substantial interest in the stationary energy storage sector due to its low cost and high energy density. However, the currently used solid electrolyte (ß-alumina) is expensive and can only be operated at high temperatures, which compromises safety. On the other hand, liquid electrolytes in room temperature sodium-sulfur batteries (RT Na-S) are susceptible to dendrite formation and polysulfide shuttle. Consequently, an electrolyte with both solid (shuttle blocking) and liquid (ionic conductivity) properties to overcome the above-mentioned issues is highly desired. Herein, a high-performance quasi-solid state crosslinked gel polymer electrolyte (GPE) prepared in situ using pentaerythritol triacrylate (PETA) exhibiting high ionic conductivity of 2.33 mS cm −1 at 25 °C is presented. The GPE-based electrolyte shows high stability resulting in a high discharge capacity of >600 mAh g s −1 after 2500 cycles with an average Coulombic efficiency of 99.91%. Density functional theory calculations reveal a weak interaction between the Na + ions and the oxygen molecules of the PETA moiety, which leads to a facile cation movement. The crosslinked polymer network is tightly connected to the cathode and can confine sulfides, thereby facilitating the conversion process.

Advancing biomedicine with gel‐based materials and composites: A comprehensive review

“…For example, sulfur can crosslink if the linear polymer contains C=C double bonds. But suppose the linear polymer contains functional groups such as carboxylic acid 8 . In that case, it can react with compounds having suitable functional groups, such as amino groups, and this method can be used for gel polymer synthesis.…”

“…But suppose the linear polymer contains functional groups such as carboxylic acid. 8 In that case, it can react with compounds having suitable functional groups, such as amino groups, and this method can be used for gel polymer synthesis. So the use of these methods is limited to polymers with a double bond or a specific functional group.…”

Additive Strategy Enhancing In Situ Polymerization Uniformity for High‐Voltage Sodium Metal Batteries

“…Owing to its merits of moderate decomposition temperature (50-80 °C), stable decomposition reaction and high operation safety, AIBN is the most commonly used initiator in thermal-induced in situ polymerized electrolytes. [32][33][34][35][36] With the gradual increase of viscosity during in situ polymerization, if the produced gas cannot be evacuated in time, they may be confined in the final electrolyte, lowering the electrolyte density and polymerization homogeneity and further impairing the electrochemical performance of batteries. Unfortunately, this issue has not received enough research attention, to the best of our knowledge.…”

Uncovering the Binder Interactions with S-PAN and MXene for Room Temperature Na–S Batteries

“…Meanwhile, diminished cathodic and anodic peaks in PAA-SM and PVDF-SM were observed, implying sluggish electrode kinetics. A double logarithmic scan rate vs peak current (Figure b and Figure S9c,d) indicates a higher k value (slope) for both the cathodic peak (A) and the anodic peak (C) for CMC-SM samples, further confirming the improved reaction kinetics as observed from the CV results . The Na + diffusion coefficient ( D Na+ ) was estimated using the Randles–Sevcik equation based on the peak current vs square root of the scan rate plot (Figure c,d and Figure S9e,f).…”

“…A double logarithmic scan rate vs peak current (Figure 4b and Figure S9c,d) indicates a higher k value (slope) for both the cathodic peak (A) and the anodic peak (C) for CMC-SM samples, further confirming the improved reaction kinetics as observed from the CV results. 51 The Na + diffusion coefficient (D Na+ ) was estimated using the Randles−Sevcik equation based on the peak current vs square root of the scan rate plot (Figure 4c,d and Figure S9e,f). The CMC-SM sample showed a balanced and higher Na + diffusion in both the anodic and cathodic regions.…”