Ti3C2 wrapped Prussian blue skeleton as an anode for potassium-ion battery

In this work, Ti3C2 MXene nanosheets are wrapped onto Prussian blue skeleton and exhibit an encouraging electrochemical performance in potassium-ion storage. In this design, the large interlayer spacing of Ti3C2 MXene and the large cavities in Prussian blue lattice can easily accommodate potassium ions. Additionally, the enclosed spaces within PB skeleton and isotropic character of amorphous Ti3C2 coating can buffer large volume strain during repeated potassium-ion intercalation and de-intercalation. This anode material can deliver a capacity of 338.4 mAh g(-1) in the 100th charge/discharge cycle at a current density of 1 A g(-1) and exhibit capacities of 287.6, 207.7 and 170.8 mAh g(-1) at 2, 5 and 10 A g(-1), respectively. By calculating the number of transferred electrons during electrochemical reaction, a potassium-ion storage mechanism is proposed, which involves an irreversible potassiation process yielding low valence iron at the beginning of electrode reaction and a reversible potassiation process between low and high valence iron in long cycle runs.

Automated summary

The research demonstrates promising electrochemical performance in potassium-ion storage by wrapping Ti3C2 MXene nanosheets onto Prussian blue skeleton. The new design allows accommodation of potassium ions and buffering of volume strain, resulting in good performance at high current densities.