High-Performance Potassium-Ion Batteries with Robust Stability Based on N/S-Codoped Hollow Carbon Nanocubes.

Currently, a big challenge for the practical use of potassium-ion batteries (PIBs) is their intrinsically poor cycling stability, due to the relatively large radius of K and sluggish kinetics for intercalation/deintercalation. Here we report the scalable fabrication of N/S-codoped hollow carbon nanocubes (NSHCCs), which have the potential as an electrode for advanced PIBs with robust stability. Their discharge and charge specific capacities are ∼560 mA h g and 310 mA h g at a current density of 50 mA g, respectively.

Robust high-temperature potassium-ion batteries enabled by carboxyl functional group energy storage.

The popularly reported energy storage mechanisms of potassium-ion batteries (PIBs) are based on alloy-, de-intercalation-, and conversion-type processes, which inevitably lead to structural damage of the electrodes caused by intercalation/de-intercalation of K with a relatively large radius, which is accompanied by poor cycle stabilities. Here, we report the exploration of robust high-temperature PIBs enabled by a carboxyl functional group energy storage mechanism, which is based on an example of p-phthalic acid (PTA) with two carboxyl functional groups as the redox centers. In such a case, the intercalation/de-intercalation of K can be performed via surface reactions with relieved volume change, thus favoring excellent cycle stability for PIBs against high temperatures.