Reviewed by Lexie CornerJan 17 2025
Researchers from Fujian Normal University have developed a novel dual salt-based quasi-solid polymer electrolyte for room-temperature Na-S batteries. This innovative electrolyte effectively mitigates the polysulfide shuttle effect and stabilizes the electrode-electrolyte interface, leading to significant performance enhancements through in situ polymerization. The study was published in the journal Energy Materials and Devices.
(a) Schematic representation of the in situ ring-opening polymerization of DOL-based electrolyte initiated by Sn(OTf)2. (b) Optical images of DS–LE and DS–QSPE. (c) 1H-NMR and (d) 13C-NMR spectra of DOL and DS–QSPE. (e) FTIR spectra of DOL, DS–LE, and DS–QSPE. Image Credit: Energy Materials and Devices, Tsinghua University Press
The high energy density and affordability of sodium-sulfur (Na-S) batteries make them attractive options for large-scale energy storage. However, several technical obstacles have prevented their widespread use. The low electrical conductivity of sulfur and its sodium polysulfide derivatives results in subpar electrochemical performance.
Furthermore, the dissolution and transport of sodium polysulfides cause capacity fade and efficiency loss over time. In addition to these problems, the development of sodium dendrites further reduces the battery's cycle life and presents serious safety hazards.
To overcome these difficulties, researchers have focused on creating sophisticated electrolytes that can efficiently regulate the movement of polysulfides and stabilize electrode/electrolyte interfaces. The researchers worked under the direction of Yuming Chen and Junxiong.
With a sodium-ion transference number of 0.73 and an impressive ionic conductivity of 4.8 × 10−4 S·cm−1 at 25 °C, the researchers' DS-QSPE significantly improves the electrochemical performance of the battery. Within the sulfurized polyacrylonitrile (SPAN) cathode, the electrolyte creates an interconnected network that offers a smooth, stable interface for electrochemical reactions.
In addition to facilitating effective and consistent ion transport, this structure maintains 81.4 % of its initial capacity by supporting a high capacity of roughly 327.4 mAh·g−1 after 200 cycles at 0.2 A·g−1. According to density functional theory calculations and molecular dynamics simulations, the DS-QSPE promotes the dissociation of sodium salts and improves the coordination of Na+ ions with the polydioxolane chain. These elements help stabilize the electrode/electrolyte interfaces and reduce the polysulfide shuttle effect, which eventually increases the battery's lifespan.
Developing a quasi-solid polymer electrolyte that can effectively address the interfacial challenges in Na-S batteries is a critical step forward in energy storage technology. Our DS-QSPE offers a reliable and scalable solution that enhances both the performance and stability of room-temperature Na-S batteries.
Junxiong Wu, Study Lead Researcher, Tsinghua University Press
The DS-QSPE offers a solution to key challenges in Na-S batteries, enabling their full potential for large-scale energy storage applications.
The advancement of quasi-solid polymer electrolytes has significant implications for the energy storage industry. This technology enhances the reliability and efficiency of energy storage systems by addressing critical issues such as interface voids and the polysulfide shuttle effect.
Furthermore, it provides a cost-effective and dependable method for energy storage, contributing to the development of a more sustainable energy future and supporting the broader adoption of renewable energy sources. The DS-QSPE represents a critical step forward in the pursuit of durable and efficient large-scale energy storage solutions as research in this field continues to evolve.
The study is supported by the FuXiaQuan National Independent Innovation Demonstration Zone Collaborative Innovation Platform, the Hundred Talents Plan of Fujian Province, the Top Young Talents of Young Eagle Program of Fujian Province, the Youth Innovation Fund of Fujian Province, the Award Program for Fujian Minjiang Scholar Professorship, the Fuan Normal University Talent Fund Program, and the National Natural Science Foundation of China.
Journal Reference:
Huang, J., et al. (2024) In situ polymerized quasi-solid polymer electrolytes enabling void-free interfaces for room-temperature sodium–sulfur batteries. Energy Materials and Devices. doi.org/10.26599/EMD.2024.9370051