Fast ion diffusion kinetics based on ferroelectric and piezoelectric effect of SnO2/BaTiO3 heterostructures for high-rate sodium storage

Acceleration of reaction kinetics is urgently pursued for high-rate sodium ion batteries, while the utilization of ferroelectric and piezoelectric effect to form local micro electric field to facilitate ion transport has rarely been reported. Herein, a coherent tin oxide/barium titanate heterostructure encapsulated inside nitrogen-doped carbon nanofibers (SnO 2 /BaTiO 3 @NCNF) is introduced as sodium ion battery anode, exhibiting high capacity retention (82% over 2000 cycles at 2 A g 1 ) and stunning long-term cyclability (183.4 mAh g 1 after 10,000 cycles at 5 A g 1 ). The local potential produced by piezoelectric and ferroelectric effect of BaTiO 3 (BTO) can boost sodium ion diffusion kinetics and promote rate performance of SnO 2 anode. The piezoelectric effect is initiated from exploiting the drawback of volume expansion of SnO 2 , while the ferroelectric effect is originated from the charge separation of polarized BTO particles under external electric field. Such principle is instructive for alloying-type and convention-type anodes of alkali-ion batteries.