The rapid research and technological improvements of sodium-ion batteries (NIBs) have made them the most practical complementary devices to lithium-ion batteries (LIBs). Furthermore, the high sodium ion diffusion kinetics offer a variety of fast-charging electrode materials that are attractive for high-power applications. However, reducing the phase-to-phase resistance and charge-transfer resistance through innovative electrolyte design, while not reducing lifetime, is critical to ensuring the safety of such applications. Herein, we report the role of low-viscosity ester-based acetate charge  in enhancing the conductivity of sodium-ion-based electrolytes. Our new electrolyte formulation has shown excellent power capability, charging 18650 cells to 84% state-of-charge (SOC) in 10 minutes. In addition, it improves low-temperature cycling performance but slightly degrades high-temperature performance compared with our co-solvent-free electrolyte. We believe that the guidelines adopted here will pave the way to find a better compromise between ultra-fast charging and high-temperature applications to achieve the best performance.
Lithium-ion batteries (LIBs) have played a key role in the electrification of transportation and smart grids in recent years. Improvements in manufacturing techniques and supply chain building have reduced the cost of Li-ion batteries from over $1000/kWh to about $1000/kWh. $200/kWh However, advances in manufacturing technology have reached their limits, and the sudden rise in the price of lithium-based precursors calls into question electrochemical energy storage that relies solely on lithium-based batteries. In addition, growing demand for low-cost batteries has raised concerns about the availability and geopolitical independence of lithium resources. To this end, sodium-ion batteries (NIBs) are attractive complementary energy storage devices due to the low-cost and population-neutrality of sodium precursors.