Interfacial Space Charge Enhanced Sodium Storage in a Zero‐Strain Cerium Niobite Perovskite Anode

Abstract

AbstractIntercalation electrode materials store Na by incorporation into their framework structure without phase transformation and substantial large volume, resulting in the excellent cycling stability during electrochemical cycling. However, challenges arise due to a low capacity of intercalation electrode for sodium‐ion batteries (SIBs). Here, a perovskite oxide (Ce1/3NbO3 (CNO)) as an intercalation anode with dual functions of high capacity and excellent cycling stability is explored. The Na+ storage capacity of CNO (141.3 mAh g‐1) originates from not only sufficient cation vacancies but also the interfacial space charge storage of Na+ in the surface of CNO particles. Additionally, CNO exhibits excellent cycling stability with 90.2% capacity retention after 1000 cycles at 1 C, 99.4% capacity retention after 2000 cycles at 5 C, and 96.5% capacity retention after 10 000 cycles at 10 C. The cycling performance can be explained by the “zero‐stain” Na+ storage characteristic, where the maximal unit cell volume variation induced by Na+ insertion/extraction is calculated to be only 0.38%. Hence, CNO is a promising alternative for long‐life SIBs. The mechanisms that enable the storage of Na+ with negligible volume variation will guide new insights for the rational design of ultra‐stable electrode materials for SIBs.