Strain Engineering in Electrochemical Activity and Stability of BiFeO₃Perovskites

Strain engineering is widely employed to manipulate the intrinsic relationship of activity and the crystal structure, while the mechanism and rational strategy toward high-performance devices are still under investigation. Here straining engineering is utilized to manipulate a series of a typical perovskite structures via introducing different types of heteroions (Bi1-xMxFeO3, M = Ca2+ or Y3+ ion). The space group R3c in BiFeO3 perovskites is found to be maintained with substituting a certain amount of heteroions at Bi3+ sites (<5%), while it would shift into either space groups P4mm (with Ca2+ substitute) or Pnma (with Y3+ substitute) beyond some critical doping amounts (>5%). Such a transformation is linked with the mismatched crystal strain induced by the heteroions substituted at Bi3+ sites, while the activity, stability, and energy storage capability of Bi1-xMxFeO3 have been essentially varied. The results offer a strategy for manipulating stability and activity of perovskites in electrochemical energy conversion and storage.