Amphicharge-Storable Pyropolymers Containing Multitiered Nanopores

In this study, hierarchically nanoporous pyropolymers (HN-PPs) including numerous redox-active heteroatoms are fabricated from polyaniline nanotubes by heating with KOH. In the large operating voltage range 1.0–4.8 V versus Li⁺/Li, HN-PPs store amphicharges by a pseudocapacitive manner of Li-ion (mainly <3.0 V) and electrochemical double layer formation of anion (primarily >3.0 V). Through these surface-driven charge storage behaviors, HN-PPs achieve a significantly high specific capacity of ≈460 mA h g⁻¹ at 0.5 A g⁻¹, maintaining specific capacities of 140 mA h g⁻¹ at a high specific current of 30 A g⁻¹ and 305 mA h g⁻¹ after 2000 cycles at 3 A g⁻¹. Furthermore, asymmetric energy storage devices based on HN-PPs deliver a high specific energy of 265 W h kg⁻¹ and high specific power of 5081 W kg⁻¹ with long-term cycling performance.