Flexible ultrathin Nitrogen-Doped carbon mediates the surface charge redistribution of a hierarchical tin disulfide nanoflake electrode for efficient capacitive deionization

Ming Gao; Wencui Liang; Zhiqian Yang; Tianqi Ao; Wenqing Chen

doi:10.1016/j.jcis.2023.07.100

Flexible ultrathin Nitrogen-Doped carbon mediates the surface charge redistribution of a hierarchical tin disulfide nanoflake electrode for efficient capacitive deionization

J Colloid Interface Sci. 2023 Nov 15;650(Pt B):1244-1252. doi: 10.1016/j.jcis.2023.07.100. Epub 2023 Jul 17.

Authors

Ming Gao¹, Wencui Liang², Zhiqian Yang¹, Tianqi Ao³, Wenqing Chen⁴

Affiliations

¹ College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
² State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China.
³ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China.
⁴ College of Architecture and Environment, Sichuan University, Chengdu 610065, China. Electronic address: wenqingchen_tea@163.com.

PMID: 37478741
DOI: 10.1016/j.jcis.2023.07.100

Abstract

Constructing pseudocapacitive electrodes with high specific capacities is indispensable for increasing the large-scale application of capacitive deionization (CDI). However, the insufficient CDI rate and cycling performance of pseudocapacitive-based electrodes have led to a decline in their use due to the corresponding volumetric expansion and contraction that occurs during long-term CDI processes. Herein, hierarchical porous SnS₂ nanoflakes are encapsulated inside an N-doped carbon (NC) matrix to achieve efficient CDI. Benefiting from the synergistic properties of the pseudocapacitive SnS₂ nanoflakes and few-layered N-doped carbon, the heterogeneous interface simultaneously provides more available vigorous sites and demonstrates rapid charge-transfer kinetics, resulting in a superior desalination capability (49.86 mg g^-1 at 1.2 V), rapid desalination rate (1.66 mg g^-1 min^-1) and better cyclic stability. Computational research reveals a work function-induced surface charge redistribution of the SnS₂@NC heterojunction, which can lead to an auspicious surface electronic structure that reduces the adsorption energy to improve the diffusion kinetics toward sodium adsorption. This work contributes to providing a thoughtful understanding of the interface engineering between transition metal dichalcogenides and NC to construct high-performance CDI electrode materials for further industrialization.

Keywords: Capacitive deionization; Density functional theory; Desalination; Flexible electrode; Heterojunction interface.