Multi-functional PEDOT-engineered sodium titanate nanowires for sodium-ion batteries with synchronous improvements in rate capability and structural stability

Qing Zhang, Yi He, Peng Mei, Xun Cui, Yingkui Yang, Zhiqun Lin

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Low electronic conductivity and poor structural stability of sodium titanate nanocrystals have restricted their potential application in sodium ion batteries (SIBs). General carbon-coating protocols at high temperature commonly initiate the surface reduction and grain growth of sodium titanate, resulting in structural distortion and sluggish ion diffusion. Herein poly(3,4-ethylenedioxythiophene) (PEDOT) encapsulated sodium titanate [NaTi3O6(OH)·2H2O, NTO] (PEDOT@NTO) composites were readily prepared by in situ oxidative polymerization of 3,4-ethylenedioxythiophene at room temperature in the presence of NTO nanowires. The as-fabricated PEDOT@NTO anode for SIBs delivers reversible capacities of 200.1 mA h g-1 at 20 mA g-1 and 80.5 mA h g-1 at 1000 mA g-1, which are much higher than 189.2 and 18.0 mA h g-1 for bare NTO at the same rates, respectively. A high capacity retention of 76.4% is also achieved for PEDOT@NTO after 1000 cycles at 200 mA g-1. Therefore, a large specific capacity and high rate and cycling capabilities are simultaneously achieved for PEDOT@NTO due to the synergistic effects of 3D architectures of intertwined nanowires and multi-functional PEDOT shells. In particular, the coated PEDOT layers effectively promote electron transport and ion diffusion, and also play a protective role in maintaining the structural stability of NTO during the charge/discharge processes. This work enables simultaneous improvements in both electronic and ionic conduction abilities of Ti-based nanomaterials, and would provide new insights into the surface engineering of nanoelectrodes with multi-functional shells.

Original languageEnglish
Pages (from-to)19241-19247
Number of pages7
JournalJournal of Materials Chemistry A
Volume7
Issue number33
DOIs
StatePublished - 2019

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© 2019 The Royal Society of Chemistry.

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