The unique structural features of hard carbon (HC) make it a promising anode candidate for sodium-ion batteries (SIB). However, traditional methods of preparing HC require special equipment, long reaction times, and large energy consumption, resulting in low throughputs and efficiency. In our contribution, a novel synthesis method is proposed, involving the formation of HC nanosheets (NS-CNs) within minutes by creating an anoxic environment through flame combustion and further introducing sulfur and nitrogen sources to achieve heteroatom doping. The effect of heterogeneous element doping on the microstructure of HC is quantitatively analyzed by high-resolution transmission electron microscopy and image processing technology. Combined with density functional theory calculation, it is verified that the functionalized HC exhibits stronger Na⁺ adsorption ability, electron gain ability, and Na⁺ migration ability. As a result, NS-CNs as SIB anodes provide an ultrahigh reversible capacity of 542.7 mAh g⁻¹ at 0.1 A g⁻¹, and excellent rate performance with a reversible capacity of 236.4 mAh g⁻¹ at 2 A g⁻¹ after 1200 cycles. Furthermore, full cell assembled with NS-CNs as the can present 230 mAh g⁻¹ at 0.5 A g⁻¹ after 150 cycles. Finally, in/ex situ techniques confirm that the excellent sodium storage properties of NS-CNs are due to the construction of abundant active sites based on the novel synthesis method for realizing the reversible adsorption of Na⁺. This work provides a novel strategy to develop novel carbons and gives deep insights for the further investigation of facile preparation methods to develop high-performance carbon anodes for alkali-ion batteries.

中文翻译：

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火焰辅助超快合成功能化碳纳米片用于高性能钠存储

硬碳（HC）独特的结构特征使其成为钠离子电池（SIB）负极的有前途的候选者。然而，传统的HC制备方法需要特殊设备、反应时间长、能耗大，导致产量和效率较低。在我们的贡献中，提出了一种新的合成方法，通过火焰燃烧创造缺氧环境，并进一步引入硫和氮源以实现杂原子掺杂，从而在几分钟内形成HC纳米片（NS-CN）。利用高分辨率透射电子显微镜和图像处理技术定量分析了异质元素掺杂对HC微观结构的影响。结合密度泛函理论计算，验证了功能化HC表现出更强的Na ⁺吸附能力、电子增益能力和Na ⁺迁移能力。因此，NS-CN作为SIB负极在0.1 A g ^{-1下提供了542.7 mAh g -1}的超高可逆容量，并且在1200年后提供了优异的倍率性能，在2 A g ^-1下可逆容量为236.4 mAh g ^-1 。循环。此外，用NS-CN组装的全电池在150次循环后可以在0.5 A g ^{-1下呈现230 mAh g -1}。最后，原位/异位技术证实，NS-CNs优异的储钠性能归因于基于新型合成方法构建的丰富的活性位点，实现了Na ⁺的可逆吸附。这项工作提供了开发新型碳的新策略，并为进一步研究开发碱离子电池高性能碳阳极的简便制备方法提供了深刻的见解。