Research Article: Smart Construction of Integrated CNTs/Li4Ti5O12 Core/Shell Arrays with Superior High‐Rate Performance for Application in Lithium‐Ion Batteries

Date Published: January 03, 2018

Publisher: John Wiley and Sons Inc.

Author(s): Zhujun Yao, Xinhui Xia, Cheng‐ao Zhou, Yu Zhong, Yadong Wang, Shengjue Deng, Weiqi Wang, Xiuli Wang, Jiangping Tu.

http://doi.org/10.1002/advs.201700786

Abstract

Exploring advanced high‐rate anodes is of great importance for the development of next‐generation high‐power lithium‐ion batteries (LIBs). Here, novel carbon nanotubes (CNTs)/Li4Ti5O12 (LTO) core/shell arrays on carbon cloth (CC) as integrated high‐quality anode are constructed via a facile combined chemical vapor deposition–atomic layer deposition (ALD) method. ALD‐synthesized LTO is strongly anchored on the CNTs’ skeleton forming core/shell structures with diameters of 70–80 nm the combined advantages including highly conductive network, large surface area, and strong adhesion are obtained in the CC‐LTO@CNTs core/shell arrays. The electrochemical performance of the CC‐CNTs/LTO electrode is completely studied as the anode of LIBs and it shows noticeable high‐rate capability (a capacity of 169 mA h g−1 at 1 C and 112 mA h g−1 at 20 C), as well as a stable cycle life with a capacity retention of 86% after 5000 cycles at 10 C, which is much better than the CC‐LTO counterpart. Meanwhile, excellent cycling stability is also demonstrated for the full cell with LiFePO4 cathode and CC‐CNTs/LTO anode (87% capacity retention after 1500 cycles at 10 C). These positive features suggest their promising application in high‐power energy storage areas.

Partial Text

Materials Synthesis: Synthesis of CC‐CNTs/LTO Electrode: First, CNTs arrays on CC were synthesized by a facile CVD with ethanol as the carbon precursor. The CC substrate was immersed in Ni(NO3)2 ethanol solution for 4 h and dried under 60 °C. Then the CC with catalyst was put into a tube furnace and treated at 600 °C under a mixed‐gas atmosphere of 140 sccm Ar + 10 sccm H2 for 30 min. Then Ar + H2 gas saturated with ethanol was introduced in the furnace for 90 min. Then, the sample was immersed into a solution with 1 m HCl and 1 m FeCl3 at 80 °C for 12 h to remove the Ni catalyst to form CC‐CNTs arrays. Second, TiO2 was fabricated on CNTs by an ALD (Beneq TFS 200) method using TiCl4 and H2O as the Ti and O precursors, respectively. Finally, the CC‐CNTs/TiO2 electrode was converted into CC‐CNTs/LTO by a simple chemical lithiation method. The as‐prepared CC‐CNTs/TiO2 electrode was placed in a 100 mL Teflon‐lined autoclave filled with 70 mL 3 m LiOH aqueous solution for 1 h at 80 °C and annealed under Ar atmosphere at 500 °C for 2 h to form CC‐CNTs/LTO core/shell arrays. The dependence of capacity and LTO mass was shown in Figure S6 (Supporting Information). The capacity would decrease as the LTO mass increases. Here, 2 mg cm−2 was selected as the representative.

The authors declare no conflict of interest.

 

Source:

http://doi.org/10.1002/advs.201700786

 

Leave a Reply

Your email address will not be published.