Pseudocapacitive Na+ Insertion in Ti-O-C Channels of TiO2-C Nanofibers with High Rate and Ultrastable Performance

Wei Song; Hanqing Zhao; Jianqi Ye; Mengmeng Kang; Siyu Miao; Zhong Li

doi:10.1021/acsami.9b02123

Pseudocapacitive Na⁺ Insertion in Ti-O-C Channels of TiO₂-C Nanofibers with High Rate and Ultrastable Performance

ACS Appl Mater Interfaces. 2019 May 15;11(19):17416-17424. doi: 10.1021/acsami.9b02123. Epub 2019 Apr 30.

Authors

Wei Song¹, Hanqing Zhao¹, Jianqi Ye¹, Mengmeng Kang¹, Siyu Miao¹, Zhong Li¹

Affiliation

¹ Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province, Institute of Coal Chemical Engineering , Taiyuan University of Technology , Taiyuan 030024 , Shanxi , China.

PMID: 31002226
DOI: 10.1021/acsami.9b02123

Abstract

Ti-O-C channels for ultrafast sodium storage were constructed in N/S-co-doped TiO₂-C nanofibers, which deliver a high rate performance of 181.9 mAh g^-1 at 5 A g^-1 after 3000 cycles. The existence of Ti-O-C bonds at the interface of TiO₂-C phases was revealed by synchrotron radiation X-ray absorption spectra. Based on this, first-principles calculations further verified the low energy barrier for Na⁺ insertion/extraction in the Ti-O-C channels formed by the intimately integrated graphite layer with TiO₂ near the surface. In addition, surface defects induced by heteroatoms accelerate the Na⁺ mass transfer through the pathway from the carbon surface to the Ti-O-C channel.

Keywords: first-principles calculations; high rate performance; pseudocapacitive; sodium-ion battery; surface defects.