Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance

Transition metal selenides are considered one of the most promising materials for sodium-ion battery anodes due to their excellent theoretical capacity. However, it remains challenging to suppress the volume variation and the resulted capacity decay during the charge–discharge process. Herein, hollo...

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Main Authors: Chao Wang, Weijie Si, Xiongwu Kang
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Inorganics
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Online Access:https://www.mdpi.com/2304-6740/13/3/96
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author Chao Wang
Weijie Si
Xiongwu Kang
author_facet Chao Wang
Weijie Si
Xiongwu Kang
author_sort Chao Wang
collection DOAJ
description Transition metal selenides are considered one of the most promising materials for sodium-ion battery anodes due to their excellent theoretical capacity. However, it remains challenging to suppress the volume variation and the resulted capacity decay during the charge–discharge process. Herein, hollow-structured CoNiSe<sub>2</sub> dual transition metal selenides wrapped in a carbon shell (HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C) were deliberately designed and prepared through sequential coating of polyacrylonitrile (PAN), ion exchange of ZIF-67 with Ni<sup>2+</sup> metal ions, and carbonization/selenization. The hollow structure was evidenced by transmission electron microscopy, and the crystalline structure was confirmed by X-ray diffraction. The ample internal space of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C effectively accommodated volume expansion during the charge and discharge processes, and the large surface area enabled sufficient contact between the electrode and electrolyte and shortened the diffusion path of sodium ions for a feasible electrochemical reaction. The surface area and ionic conductivity of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C were strongly dependent on the ratio of Co to Ni. The synergistic effect between Co and Ni enhanced the conductivity and electron mobility of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C, thereby improving charge transfer efficiency. By taking into account the structural advantages and rational metal selenide ratios, significant improvements can be achieved in the cycling performance, rate performance, and overall electrochemical stability of sodium-ion batteries. The optimized HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C demonstrated excellent performance, and the reversible capacity remained at 334 mAh g<sup>−1</sup> after 1000 cycles at a high current of 5.0 A g<sup>−1</sup>.
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spelling doaj-art-c2c6ed6e78a64db48e62da18de4554992025-08-20T02:42:31ZengMDPI AGInorganics2304-67402025-03-011339610.3390/inorganics13030096Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery PerformanceChao Wang0Weijie Si1Xiongwu Kang2National Institute of Guangdong Advanced Energy Storage, Guangzhou 510000, ChinaNew Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaNew Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou 510006, ChinaTransition metal selenides are considered one of the most promising materials for sodium-ion battery anodes due to their excellent theoretical capacity. However, it remains challenging to suppress the volume variation and the resulted capacity decay during the charge–discharge process. Herein, hollow-structured CoNiSe<sub>2</sub> dual transition metal selenides wrapped in a carbon shell (HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C) were deliberately designed and prepared through sequential coating of polyacrylonitrile (PAN), ion exchange of ZIF-67 with Ni<sup>2+</sup> metal ions, and carbonization/selenization. The hollow structure was evidenced by transmission electron microscopy, and the crystalline structure was confirmed by X-ray diffraction. The ample internal space of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C effectively accommodated volume expansion during the charge and discharge processes, and the large surface area enabled sufficient contact between the electrode and electrolyte and shortened the diffusion path of sodium ions for a feasible electrochemical reaction. The surface area and ionic conductivity of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C were strongly dependent on the ratio of Co to Ni. The synergistic effect between Co and Ni enhanced the conductivity and electron mobility of HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C, thereby improving charge transfer efficiency. By taking into account the structural advantages and rational metal selenide ratios, significant improvements can be achieved in the cycling performance, rate performance, and overall electrochemical stability of sodium-ion batteries. The optimized HS-Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub>@C demonstrated excellent performance, and the reversible capacity remained at 334 mAh g<sup>−1</sup> after 1000 cycles at a high current of 5.0 A g<sup>−1</sup>.https://www.mdpi.com/2304-6740/13/3/96sodium-ion batteryhollow structurebinary transition metal selenidessynergistic effect
spellingShingle Chao Wang
Weijie Si
Xiongwu Kang
Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
Inorganics
sodium-ion battery
hollow structure
binary transition metal selenides
synergistic effect
title Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
title_full Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
title_fullStr Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
title_full_unstemmed Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
title_short Hollow-Structured Carbon-Coated Co<sub>x</sub>Ni<sub>y</sub>Se<sub>2</sub> Assembled with Ultrasmall Nanoparticles for Enhanced Sodium-Ion Battery Performance
title_sort hollow structured carbon coated co sub x sub ni sub y sub se sub 2 sub assembled with ultrasmall nanoparticles for enhanced sodium ion battery performance
topic sodium-ion battery
hollow structure
binary transition metal selenides
synergistic effect
url https://www.mdpi.com/2304-6740/13/3/96
work_keys_str_mv AT chaowang hollowstructuredcarboncoatedcosubxsubnisubysubsesub2subassembledwithultrasmallnanoparticlesforenhancedsodiumionbatteryperformance
AT weijiesi hollowstructuredcarboncoatedcosubxsubnisubysubsesub2subassembledwithultrasmallnanoparticlesforenhancedsodiumionbatteryperformance
AT xiongwukang hollowstructuredcarboncoatedcosubxsubnisubysubsesub2subassembledwithultrasmallnanoparticlesforenhancedsodiumionbatteryperformance