Ultrathin Al 2 O 3 ‐Coated Biomass Carbon for Sodium‐Ion Batteries via a Synergistic Storage Mechanism

作者：Junjun Zhou, Xiaofan Shi, Yanwen Song, Hui‐Lin Huang, Lei Wang, Yuhui Zhai, Qing Han, Lingling Xie, Xuejing Qiu, Hongjun Chen, Yuling Wang, Guangshan Zhu, Limin Zhu, Xiaoyu Cao · 发表于：Carbon Energy · 年份：2025 · DOI：10.1002/cey2.70121 · 被引用次数：2 · 研究领域：Advancements in Battery Materials、Advanced Battery Materials and Technologies、Advanced battery technologies research

ABSTRACT Hard carbon (HC) is a promising anode candidate for sodium‐ion batteries (SIBs), yet its application is plagued by unstable interfaces and poor long‐term cyclability. Herein, we develop a facile solvent evaporation strategy to synthesize ultrathin Al 2 O 3 ‐coated biomass‐derived HC (GSC‐Al 2 O 3 ‐3%). The conformal Al 2 O 3 layer passivates defects and micropores, suppresses side reactions, and promotes the formation of a robust organic–inorganic hybrid solid electrolyte interphase. Comprehensive characterizations, including in situ X‐ray diffraction, ex situ Raman spectra, X‐ray photoelectron spectroscopy, time of flight secondary ion mass spectrometry, solid‐state 27 Al nuclear magnetic resonance, and atomic force microscope modulus mapping, demonstrate that Al 2 O 3 actively participates in SEI reconstruction, enhancing the chemical and mechanical stability. Electrochemical tests reveal that the optimized GSC‐Al 2 O 3 ‐3% anode delivers 91% capacity retention after 1000 cycles at 1.0 A g −1 , and possesses excellent wide‐temperature tolerance (149.3 mAh g⁻¹ at −30°C and 286.8 mAh g −1 at 60°C). Mechanistic studies confirm a synergistic Na + storage process involving “adsorption–intercalation–pore filling,” while density functional theory calculations and electrostatic potential mapping reveal that Al 2 O 3 coating regulates interfacial charge distribution and reduces Na + migration barriers. A full cell paired with a NaNi 0.5 Fe 0.5 MnO 4 cathode exhibits a high ...