A redox-active Fe(CN)6−4-doped polypyrrole was synthesized and found to have a remarkable redox capacity of 135 mA h g−1 in Na+ electrolyte, an excellent rate capability of 1600 mA g−1 and a strong capacity retention of 85% over 100 cycles, showing great promise for enabling low-cost and environmentally benign Na-ion batteries for large-scale electric energy storage.
