Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes

Hard carbon anodes are promising for sodium-ion batteries due to their low cost and high reversible capacity. However, the long-term Na<sup>+</sup> (de)intercalating process destroys the structure of the two-phase interface between the electrode and electrolyte, impairing cycling stabili...

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Main Authors: Bo Zhu, Tiany Ji, Qiong Liu, Lixin Li
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Batteries
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Online Access:https://www.mdpi.com/2313-0105/11/5/203
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author Bo Zhu
Tiany Ji
Qiong Liu
Lixin Li
author_facet Bo Zhu
Tiany Ji
Qiong Liu
Lixin Li
author_sort Bo Zhu
collection DOAJ
description Hard carbon anodes are promising for sodium-ion batteries due to their low cost and high reversible capacity. However, the long-term Na<sup>+</sup> (de)intercalating process destroys the structure of the two-phase interface between the electrode and electrolyte, impairing cycling stability. In this paper, a few-layer graphene (FLG)-coated hard carbon fiber composite is constructed. A uniform graphene encapsulation is confirmed by synchrotron small-angle X-ray scattering and transmission electron microscopy technologies. Post-cycling observation reveals FLG participation in forming a hybrid solid electrolyte interphase (SEI). At a proper concentration, the FLG with a small specific surface area and pore size characteristics is well matched in the SEI. The FLG-integrated SEI not only mitigates volume expansion but also enhances ion conductivity through its oxygen-rich functional groups. As a result, the composite structure maintains 98.2% capacity retention after 100 cycles and reaches 164 mAh g<sup>−1</sup> at 1000 mA g<sup>−1</sup>, compared to 97 mAh g<sup>−1</sup> for the pristine hard carbon. This work demonstrates that FLG coating simultaneously stabilizes the interfacial chemistry and improves the ion transport, offering a practical pathway to advance hard carbon anodes for high-performance sodium-ion batteries.
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spelling doaj-art-7c3d796b63eb499aaecc17a399ea28272025-08-20T01:56:25ZengMDPI AGBatteries2313-01052025-05-0111520310.3390/batteries11050203Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite ElectrodesBo Zhu0Tiany Ji1Qiong Liu2Lixin Li3School of Innovation and Entrepreneurship, Heilongjiang University of Science & Technology, Harbin 150020, ChinaSchool of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021, ChinaXi’an Herong New Energy Technology Co., Ltd., Xi’an 710018, ChinaSchool of Innovation and Entrepreneurship, Heilongjiang University of Science & Technology, Harbin 150020, ChinaHard carbon anodes are promising for sodium-ion batteries due to their low cost and high reversible capacity. However, the long-term Na<sup>+</sup> (de)intercalating process destroys the structure of the two-phase interface between the electrode and electrolyte, impairing cycling stability. In this paper, a few-layer graphene (FLG)-coated hard carbon fiber composite is constructed. A uniform graphene encapsulation is confirmed by synchrotron small-angle X-ray scattering and transmission electron microscopy technologies. Post-cycling observation reveals FLG participation in forming a hybrid solid electrolyte interphase (SEI). At a proper concentration, the FLG with a small specific surface area and pore size characteristics is well matched in the SEI. The FLG-integrated SEI not only mitigates volume expansion but also enhances ion conductivity through its oxygen-rich functional groups. As a result, the composite structure maintains 98.2% capacity retention after 100 cycles and reaches 164 mAh g<sup>−1</sup> at 1000 mA g<sup>−1</sup>, compared to 97 mAh g<sup>−1</sup> for the pristine hard carbon. This work demonstrates that FLG coating simultaneously stabilizes the interfacial chemistry and improves the ion transport, offering a practical pathway to advance hard carbon anodes for high-performance sodium-ion batteries.https://www.mdpi.com/2313-0105/11/5/203hard carbonfew-layer graphenesodium-ion batterysolid electrolyte interface
spellingShingle Bo Zhu
Tiany Ji
Qiong Liu
Lixin Li
Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
Batteries
hard carbon
few-layer graphene
sodium-ion battery
solid electrolyte interface
title Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
title_full Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
title_fullStr Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
title_full_unstemmed Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
title_short Enhanced Sodium Storage Performance of Few-Layer Graphene-Encapsulated Hard Carbon Fiber Composite Electrodes
title_sort enhanced sodium storage performance of few layer graphene encapsulated hard carbon fiber composite electrodes
topic hard carbon
few-layer graphene
sodium-ion battery
solid electrolyte interface
url https://www.mdpi.com/2313-0105/11/5/203
work_keys_str_mv AT bozhu enhancedsodiumstorageperformanceoffewlayergrapheneencapsulatedhardcarbonfibercompositeelectrodes
AT tianyji enhancedsodiumstorageperformanceoffewlayergrapheneencapsulatedhardcarbonfibercompositeelectrodes
AT qiongliu enhancedsodiumstorageperformanceoffewlayergrapheneencapsulatedhardcarbonfibercompositeelectrodes
AT lixinli enhancedsodiumstorageperformanceoffewlayergrapheneencapsulatedhardcarbonfibercompositeelectrodes