Low temperature molten salt reduction has been demonstrated as the most intriguing approach to prepare silicon–carbon hybrid anode materials due to its cost-effectivity and scalability. However, a common issue plaguing this method is the controllability of product morphology. Herein, a carbon network strategy was proposed to explore the influence of carbon distribution in silicon oxide/carbon nanocomposites on the morphology transition during molten salt reduction. The result shows that the densification of the three-dimensional carbon framework affects the kinetics of the reduction process, thus achieving distinct morphologies of the final product. An appropriate carbon network is conducive to forming porous Si/SiO_x/C hollow spheres, while a dense carbon network will hinder the internal diffusion and form a pitaya-like structure. When the carbon network is too sparse or without carbon, the reduction products tend to collapse to form irregular aggregates. As a lithium-ion battery anode, the Si/SiO_x/C nanocomposite with a hollow sphere structure manifests outstanding electrochemical performance in terms of superior cycling stability and excellent rate performance. The current work can provide new insights into the preparation of carbon–silicon based composites with various morphologies via the molten salt method.

中文翻译：

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碳网络策略，可在熔融盐还原过程中使硅碳阳极朝规定的形态合成

低温熔融盐还原由于具有成本效益和可扩展性，已被证明是制备硅碳混合阳极材料的最引人入胜的方法。但是，困扰该方法的一个常见问题是产品形态的可控性。在此，提出了一种碳网络策略来探索氧化硅/碳纳米复合材料中碳分布对熔融盐还原过程中形态转变的影响。结果表明，三维碳骨架的致密化影响了还原过程的动力学，从而实现了最终产品的独特形态。适当的碳网络有利于形成多孔Si / SiO _x/ C空心球，而致密的碳网络将阻碍内部扩散并形成类似火龙果的结构。当碳网络太稀疏或没有碳时，还原产物往往会塌陷而形成不规则的聚集体。作为锂离子电池负极，具有中空球形结构的Si / SiO _x / C纳米复合材料在优异的循环稳定性和优异的倍率性能方面表现出出色的电化学性能。当前的工作可以为通过熔融盐法制备具有各种形态的碳硅基复合材料提供新的见解。