(001) Facet-Dominated Hierarchically Hollow Na2Ti3O7 as a High-Rate Anode Material for Sodium-Ion Capacitors

Hao Chen; Yuanke Wu; Jingjing Duan; Renming Zhan; Wei Wang; Min-Qiang Wang; Yuming Chen; Maowen Xu; Shu-Juan Bao

doi:10.1021/acsami.9b14560

(001) Facet-Dominated Hierarchically Hollow Na₂Ti₃O₇ as a High-Rate Anode Material for Sodium-Ion Capacitors

ACS Appl Mater Interfaces. 2019 Nov 13;11(45):42197-42205. doi: 10.1021/acsami.9b14560. Epub 2019 Nov 1.

Authors

Hao Chen¹, Yuanke Wu¹, Jingjing Duan², Renming Zhan¹, Wei Wang¹, Min-Qiang Wang¹, Yuming Chen³, Maowen Xu¹, Shu-Juan Bao¹

Affiliations

¹ Institute for Clean Energy & Advanced Materials, School of Materials and Energy , Southwest University , Chongqing 400715 , PR China.
² School of Chemical Engineering , The University of Adelaide , Adelaide , South Australia 5005 , Australia.
³ Department of Nuclear Science and Engineering, Department of Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States.

PMID: 31637910
DOI: 10.1021/acsami.9b14560

Abstract

Sodium-ion capacitors (SICs) have shown great potential to combine the merits of high-power capability of traditional capacitors and high energy capability of batteries. However, the sluggish kinetics and inferior stability of conventional sodium-ion storage anode materials are major challenges for the practical utilization of SICs. In this work, interconnected urchin-like hollow Na₂Ti₃O₇ (Na₂Ti₃O₇-IcUH) chains were designed and prepared by a simple one-step template-assisting method. Through a variety of controlled experiments, we explored how to effectively engineer the crystal-oriented growth and string the urchin-like spheres together. Benefiting from its urchin-like hollow structure and fully exposed (001) facet, the resulting Na₂Ti₃O₇-IcUH exhibits a superior rate capability of 96.2 mA h g^-1 at 5 A g^-1. Meanwhile, the interconnected three-dimensional primary structure endows Na₂Ti₃O₇-IcUH with excellent cyclic stability (15% capacity loss at 5 A g^-1 after 2000 cycles). By coupling with commercial active carbon, the assembled SIC successfully demonstrates a energy density of 134.3 W h kg^-1 at a power density of 125 W kg^-1 and 38.2 W h kg^-1 at a high-power density of 2500 W kg^-1, as well as a superior capacity retention of 75% after 2000 cycles at 2 A g^-1 within 1-4 V.

Keywords: controlled synthesis; dominated exposed (001) facet; high-rate performance; interconnected urchin-like hollow Na2Ti3O7; sodium-ion capacitors.