The low-cost and high-capacity SiO_x is widely recognized as an ideal anode material for lithium storage; however, the challenges of low conductivity and significant volume expansion still need to be addressed. In this work, we incorporated SiO_x into a lignin-derived carbon material with an elevated nitrogen content through a step-by-step carbonization strategy. Initially, the electrostatic assembly facilitated the formation of a complex comprising modified lignin and SiO₂, which was subsequently subjected to carbonization and etching steps. Finally, due to zinc species inhibiting nitrogen decomposition, the cocarbonization of the lignin porous carbon/SiO_x complex, zinc oxalate, and melamine enabled the construction of a nitrogen-enriched carbon/SiO_x composite. The resulting carbon/SiO_x composite exhibited a moderate specific surface area, abundant mesoporous channels, and an exceptionally high nitrogen doping content of 17.91 at. %. These characteristics effectively enhanced the storage and transportation of lithium ions while mitigating the volume expansion. As anodes in half batteries, the reversible specific capacity of the optimized carbon/SiO_x reached 894 mAh/g during stable cycles, which was attributed to the enhanced ion diffusion rate and storage kinetics resulting from the high nitrogen content as well as the improved structural stability due to the encapsulated structure. Furthermore, the assembled lithium-ion capacitor demonstrated an energy density of 82 Wh/kg and maintained a capacity retention rate of 93.1% after undergoing 15,000 cycles. This work presents a novel concept for the synthesis of nitrogen-rich carbon matrixes but also offers insights into the structural optimization of silicon-based negative electrodes using green biomass.

中文翻译：

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SiOx 封装在富氮木质素多孔碳中，用于快速锂储存


低成本、高容量的 SiO_x 被广泛认为是理想的锂存储负极材料;然而，低电导率和显著体积膨胀的挑战仍然需要解决。在这项工作中，我们通过逐步碳化策略将 SiO_x 掺入含氮量升高的木质素衍生碳材料中。最初，静电组装促进了由改性木质素和 SiO₂ 组成的复合物的形成，随后进行了碳化和蚀刻步骤。最后，由于锌种类抑制氮分解，木质素多孔碳/SiO_x 复合物、草酸锌和三聚氰胺的共碳化使富氮碳/SiO_x 复合材料的构建成为可能。所得的碳/SiO_x 复合材料表现出适中的比表面积、丰富的介孔通道和 17.91 at 的极高氮掺杂含量。%.这些特性有效地增强了锂离子的储存和运输，同时减轻了体积膨胀。作为半电池中的负极，优化后的 carbon/SiO_x 在稳定循环期间的可逆比容量达到 894 mAh/g，这归因于高氮含量导致的离子扩散速率和存储动力学增强，以及封装结构提高了结构稳定性。此外，组装好的锂离子电容器的能量密度为 82 Wh/kg，在经过 15,000 次循环后保持了 93.1% 的容量保持率。 这项工作提出了一种合成富氮碳基质的新概念，但也为使用绿色生物质的硅基负极的结构优化提供了见解。