1成果简介 

　　生物质衍生硬碳（HC）作为钠离子电池（SIBs）低成本负极材料备受瞩目。然而，传统热解通常导致窄石墨层间距和无序微结构，严重阻碍Na⁺扩散动力学并限制低压平台容量。本文，中国林业科学研究院王傲、孙康，南京林业大学范孟孟 副教授等在《Advanced Functional Materials》期刊发表名为"Joule Heating Triggered Interfacial Engineering of Biomass Hard Carbon for High-Performance Sodium-Ion Batteries"的论文，研究开发了一种铁介导的焦耳加热策略，在超快时间尺度上精确调控竹子衍生硬碳的微结构。

　　快速碳原子重构与Fe催化石墨化的协同作用，同时实现了扩大的层间距、发达的闭孔结构以及长程有序的扩展石墨微晶，共同促进更快的Na⁺扩散与存储。值得注意的是，微量残余Fe进一步调控界面化学，降低电解质分解能垒，促进形成薄而均匀的无机富集固体电解质界面膜（SEI）。得益于微结构与界面化学的双重调控，所得硬碳在0.05 A g⁻¹下可逆容量达395 mAh g⁻¹（含297 mAh g⁻¹的高平台容量），并在5000次循环后保持84%的初始容量，优于已报道的生物质衍生硬碳负极。该工作将金属残留物从"感知杂质"转化为功能性界面调控剂，为高性能生物质硬碳负极提供了一条快速且可扩展的制备路线。

　　2图文导读  

　　图1、(a) Schematic illustration of the synthesis procedure. HR-TEM and mapping images of (b–e) FHC-J and (f–i) FHC-T. (j) XRD patterns. (k) La and Lc were calculated based on XRD. (l) The interlayer spacing of samples.

　　图2、(a) N2 adsorption/desorption isotherms. (b) Microporous pore size distribution. (c) CO2 adsorption/desorption isotherms. (d) Ultra-micropores size distribution. (e) SAXS curves. (f) Closed pore volume and true density. (g) Near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and magnified image of FHC-J and HC-T. (h) Raman spectra.

　　图3. (a) GCD profiles at 0.05 A g−1of different samples. (b) Sloping/plateau capacity contribution comparison. (c) Rate capability of different samples. (d) Cycling stability at 1 A g−1. (e) Comparison of performance of FHC-J with previously reported materials. (f) Schematic of a sodium-ion full-cell with FHC-J anode and an NVP cathode. (g) GCD of FHC-J//NVP SIB at various current densities. (h) Rate the performance of FHC-J//NVP.

　　图4、(a) Na adsorption energies. (b) Simulation and calculation of diffusion models of FHC-J and HC-T. (c) Na diffusion pathway. (d) GITT of HC-T, HC-J, FHC-T, and FHC-J during the sodiation. (e) GITT of HC-T, HC-J, FHC-T, and FHC-J during the desodiation. (f) Colorimetry experiment of FHC-J electrodes at different voltages in an ethanol solution containing phenolphthalein. (g) In situ Raman pattern during the discharge process of the FHC-J anode. (h) In situ Raman pattern during the charge process of the FHC-J anode.

　　图5. (a–d) HR-TEM image of FHC-J and HC-T electrode (0.1 A g−1, after the 10th and 100th cycles). (e) 3D topographical AFM images of FHC-J and HC-T anodes. Depth-profiling XPS spectra of Fe 2p (f) and F 1s (g, h) of SEI on anodes. In situ Nyquist plots of (i) the FHC-J and (j) the HC-T electrodes at the discharging stage from 1.5 to 0.01 V. (k) Ed of the P─F bond for FHC-J and HC-T electrode interfaces. (l) Schematic illustration of SEI formation in electrolyte.

　　图6、(a) HR-TEM images of Co-HC-J. (b) HR-TEM images of Ni-HC-J. (c) Comparison of electrochemical properties of HC mediated by different metals. (d) HR-TEM images of Tree-FHC-J. (e) HR-TEM images of Shell-FHC-J. (f) Comparison of electrochemical properties of HC from different precursors. (g) Analysis of the process of biomass pyrolysis to carbon.

　　3小结 

　　本文提出了一种铁介导的焦耳加热策略，用于重构生物质衍生的硬碳（HC），以作为钠离子电池（SIBs）的负极材料。这种方法通过超快电热过程，促进了长程有序石墨域的形成，同时避免了层间压实和过度缺陷的产生

　　研究结果表明，优化后的FHC-J电极在0.05 A g⁻¹电流密度下，可逆容量高达395 mAh g⁻¹，并且相应的全电池实现了180 mAh g⁻¹的实用容量。此外，残余的铁还通过降低电解质解离势垒来调节界面化学，促进了无机NaF的形成，并构建了稳定的固体电解质界面（SEI）层。因此，基于FHC-J的SIBs在5000次循环后仍能保持84%的容量。该方法适用于多种生物质前驱体，为解决HC负极的长期限制并推动高性能SIBs的发展提供了一条可靠途径。

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