Unlocking Enhanced Capacitive Deionization of NaTi2(PO4)3/Carbon Materials by the Yolk-Shell Design

Xiaohong Liu; Xingtao Xu; Xiaoxu Xuan; Wei Xia; Guilin Feng; Shuaihua Zhang; Zhen-Guo Wu; Benhe Zhong; Xiaodong Guo; Keyu Xie; Yusuke Yamauchi

doi:10.1021/jacs.3c01755

Unlocking Enhanced Capacitive Deionization of NaTi₂(PO₄)₃/Carbon Materials by the Yolk-Shell Design

J Am Chem Soc. 2023 Apr 26;145(16):9242-9253. doi: 10.1021/jacs.3c01755. Epub 2023 Apr 14.

Authors

Xiaohong Liu¹, Xingtao Xu^{2

3}, Xiaoxu Xuan⁴, Wei Xia⁵, Guilin Feng⁶, Shuaihua Zhang⁷, Zhen-Guo Wu⁸, Benhe Zhong⁸, Xiaodong Guo⁸, Keyu Xie¹, Yusuke Yamauchi^{3

9

10}

Affiliations

¹ State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an 710072, P. R. China.
² Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, China.
³ International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
⁴ Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China.
⁵ School of Chemistry and Molecular Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, Shanghai 200062, China.
⁶ Research Institute for Electronic Science (RIES), Hokkaido University, N20W10, Sapporo City 001-0020, Japan.
⁷ Department of Chemistry, College of Science, Hebei Agricultural University, Baoding 071001, China.
⁸ School of Chemical Engineering, Sichuan University, Chengdu 610065, China.
⁹ School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia.
¹⁰ Department of Materials Science and Engineering, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.

PMID: 37058355
DOI: 10.1021/jacs.3c01755

Abstract

The low salt adsorption capacities (SACs) of benchmark carbon materials (usually below 20 mg g^-1) are one of the most challenging issues limiting further commercial development of capacitive deionization (CDI), an energetically favorable method for sustainable water desalination. Sodium superionic conductor (NASICON)-structured NaTi₂(PO₄)₃ (NTP) materials, especially used in combination with carbon to prepare NTP/C materials, provide emerging options for higher CDI performance but face the problems of poor cycling stability and dissolution of active materials. In this study, we report the development of the yolk-shell nanoarchitecture of NASICON-structured NTP/C materials (denoted as ys-NTP@C) using a metal-organic framework@covalent organic polymer (MOF@COP) as a sacrificial template and space-confined nanoreactor. As expected, ys-NTP@C exhibits good CDI performance, including exemplary SACs with a maximum SAC of 124.72 mg g^-1 at 1.8 V in the constant-voltage mode and 202.76 mg g^-1 at 100 mA g^-1 in the constant-current mode, and good cycling stability without obvious performance degradation or energy consumption increase over 100 cycles. Furthermore, X-ray diffraction used to study CDI cycling clearly exhibits the good structural stability of ys-NTP@C during repeated ion intercalation/deintercalation processes, and the finite element simulation shows why yolk-shell nanostructures exhibit better performance than other materials. This study provides a new synthetic paradigm for preparing yolk-shell structured materials from MOF@COP and highlights the potential use of yolk-shell nanoarchitectures for electrochemical desalination.