The smart electrolyte the researchers developed is a novel and “active” strategy to build thermally safe electrochemical energy storage devices because it can self-suppress the heat generation at elevated temperature while resuming to original working state with high performance at normal temperature.
UT Austin Researchers: Ye Shi, Materials Science & Engineering Graduate Student; Heonjoo Ha, Chemical Engineering Scientist Associate; Atheer Al-Sudani, Mechanical Engineering Graduate Student; Christopher J. Ellison, Chemical Engineering Adjunct Associate Professor; Guihua Yu, Mechanical Engineering Assistant Professor
Discovery: A low-cost, smart electrolyte showing reversible solid-gel transition at elevated temperature that enables thermally self-regulating electrochemical energy storage devices.
Why It Matters: Researchers around the globe have been trying to build powerful electrochemical energy storage devices that can withstand the heat of fast charging and discharging and also avoid thermal runaway, especially in large-scale (or even grid) applications such as electrical vehicles. Existing conventional strategies are generally “passive,” as they usually harm the device performance and lack sensitivity to temperature change. The smart electrolyte we developed is a novel and “active” strategy to build thermally safe electrochemical energy storage devices because it can self-suppress the heat generation at elevated temperature while resuming to original working state with high performance at normal temperature.
This smart electrolyte shows great potential for industrial manufacturing owing to its simple preparation, high tunability and versatility. The polymer can be directly added into the commercialized electrolyte and to create a safe device. If brought to market, electrochemical devices using this smart electrolyte could revolutionize the energy storage industry, touching scores of everyday technologies.
How: The researchers added the commercialized block polymer Pluronic to electrolyte in energy storage devices. Pluronic contains two segments of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) in its polymer backbone, which are hydrophilic and hydrophobic, respectively. Pluronic solution shows reversible sol-gel transition with the change of temperature. At low temperature, the Pluronic forms small micelles in solution and the electrolyte is in solution state, thus the ions could move freely between electrodes. When temperature increases, the electrolyte changes to gel state since the PEO chains are stretched and the micelles are entangled with each other (as shown in scheme), thus the motion of ions is inhibited, which finally shuts down the electrochemical devices. Based on this reversible process, thermal-responsive electrochemical devices with self-protection function can be developed.
Published: Advanced Materials, “Thermoplastic elastomer enabled smart electrolyte for thermal-responsive self-protection of electrochemical energy storage devices.”
What’s Next: The researchers are extending this smart electrolyte from aqueous system to a number of different organic solvents and they are also exploiting new thermally self-regulating devices beyond supercapacitors to various batteries and other electrochemical energy devices.