High-capacity polymer electrodes for potassium batteries

We synthesized and investigated a series of six promising polymeric electrode materials, which incorporate multiple redox-active groups enabling high specific discharge capacity and energy density in potassium half-cells. All investigated polymers showed a discharge capacity exceeding 200 mA h g−1 and no capacity fading after several hundred charge–discharge cycles. The best-performing material P1 delivered a discharge capacity of 422 mA h g−1 and record-high energy density of ∼696 W h kg−1 at 0.5 A g−1 in combination with a specific power of >20 000 W kg−1 reached at a specific current of 12 A g−1. The obtained results place P1 among the best electrode materials reported so far for potassium-ion batteries.