Ex-situ charge-discharge XANES study and device performance of a highly stable sodium-ion capacitor from cerium oxide-cerium titanate-reduced graphene oxide composite

Authored by

N. Gnanaseelan, P. Elumalai, S. Archana, R. Colina-Ruiz, F. J. Espinosa-Faller, J. Mustre, L. E. Arvizu-Rodriguez, Max Marian, F. Caballero-Briones

Abstract

A CeO_2-x-Ce₂Ti₃O_8.7-reduced graphene oxide composite was synthesized by a two-step method consisting of an alkaline treatment of TiO₂ nanoparticles, followed by hydrothermal reaction of Ce(NO₃)₃ and graphene oxide. Transmission electron microscopy and X-ray diffraction revealed CeO₂ nanoparticles directly decorating the GO sheet edges, while cerium titanate nanoparticles mostly intercalate between rGO sheets. The electrochemical characterization confirmed Faradaic and non-Faradaic responses. Ex-situ X-ray absorption near edge spectroscopy performed in pristine, single charged, single discharged, and 10 cycle charge-discharged CTG electrodes, demonstrated that reversible sodiation proceeds by Na intercalation within the Ce voids at the Ce titanate, Na reaction with CeO_2-x, and Na adsorption at the rGO oxygen moieties. Cycling stability was attributed to the reversibility of the Ce4+/Ce3+ redox reaction, Na mobility aided by oxygen vacancies, and rGO's role in buffering the volume change, while allowing rapid charge transfer through s and π states. Coin cell device exhibited a maximum energy of 50 Wh kg−1 and power density of 645 Wkg-1 at 4.8 Ag-1, with 97% charge retention after 5000 cycles at 2 Ag-1, making the CTG system promising for large, reversible sodium ion storage.

Details

Organisation(s): Institute of Machine Elements and Engineering Design
External Organisation(s): Pontificia Universidad Católica de Chile
Pondicherry University
University of Chicago
Universidad Marista de Mérida
Center for Research and Advanced Studies of the National Polytechnic Institute
Instituto Tecnológico de Ciudad Madero
Instituto Politecnico Nacional
Type: Article
Journal: Journal of power sources
Volume: 684
ISSN: 0378-7753
Publication date: 19.05.2026
Publication status: E-pub ahead of print
Peer reviewed: Yes
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Physical and Theoretical Chemistry, Electrical and Electronic Engineering
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1016/j.jpowsour.2026.240425 (Access: Closed )