Spongy p‑Toluenesulfonic Acid-doped Polypyrrole with Extraordinary Rate Performance as Durable Anodes of Sodium-Ion Batteries at Different Temperatures

Sodium-ion batteries (SIBs) have potential as an energy storage system because they have similar electrochemical properties as lithium-ion batteries, abundant resource reserves, and extremely high safety performance. Compared with traditional graphite materials, conductive polymers are more suitable as an anode electrode material for SIBs. In this study, a simple and scalable approach has been used to synthesize p-toluenesulfonic acid-doped polypyrrole (p-TSA-PPy). The as-obtained material showed remarkable rate capacities and cyclability. At room temperature (25 °C), its discharge capacities could reach 185, 162, and 135 mAh g–1 under 10, 30, and 50 C rates after 250 cycles, respectively. More importantly, the capacity of the p-TSA-PPy could still be maintained at 120.5 mAh g–1 even at the 2000th cycle at 10 C. In addition, it achieves attractive electrochemical performance at different temperatures (0 and 50 °C).