Multi-functional PEDOT-engineered sodium titanate nanowires for sodium–ion batteries with synchronous improvements in rate capability and structural stability. Issue 33 (16th July 2019)

• Record Type: Journal Article
• Authors: Zhang, Qing; He, Yi; Mei, Peng; Cui, Xun; Yang, Yingkui; Lin, Zhiqun
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 33(2019)
• Page Start: 19241
• Page End: 19247
• Publication Date: 2019-07-16
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta04406j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : PEDOT-encapsulated sodium titanate nanowires with improved rate capability and structural stability arising from bridged networks and multi-functional PEDOT shells. 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 [NaTi3 O6 (OH)·2H2 O, 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.