The ultra-high theoretical capacity of silicon-based (Si) materials makes them promising anode materials for high energy density lithium-ion batteries. Unfortunately, the dramatic volume change (∼300%) and low electrical conductivity of silicon have severely hindered the commercial use of silicon anodes. Silicon suboxide (SiOx) is one of the ideal candidates for high energy density batteries due to its reduced swelling and lower cost as compared to silicon. However, it remains a huge challenge to address the low conductivity, low (initial) coulombic efficiency and apparent volume effects of SiOx. In this paper, SiOx/Co@C composite anode materials loaded with metal Co nanoparticles were uniformly and efficiently prepared by using 3-aminopropyl triethoxysilane (APTES) as silicon source and Co-MOF as Co source via molecular self-assembly strategy. The experimental results and density functional theory (DFT) calculation showed that the catalytic action of embedded Co nanoparticles had activated the silico-oxygen bond of SiOx and the irreversible product Li2O, thereby improving the initial coulombic efficiency (ICE) and enhancing the reversible capacity. At the same time, the metal Co with mechanical rigidity and electrical conductivity alleviated the volume fluctuation during alloying and improved the charge transfer capacity and ion transport rate of the composite. When compared with SiOx@C anodes, SiOx/Co@C-600 composites showed higher initial CE, superior cyclic stability and good rate performance. In particular, the successful matching of the anode with the lithium iron phosphate (LFP) cathode in full cell systems validated the possibility of its practical application. This work provides important insights into the application of Si-based materials in lithium-ion battery electrode materials and the development of high energy density batteries.

中文翻译：

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MOF 衍生的钴纳米粒子在低氧化硅基阳极中用于增强锂存储


硅基（Si）材料的超高理论容量使其成为高能量密度锂离子电池的有前途的负极材料。不幸的是，硅巨大的体积变化（~300%）和低电导率严重阻碍了硅阳极的商业应用。低氧化硅（SiOx）是高能量密度电池的理想候选材料之一，因为与硅相比，它的膨胀更少且成本更低。然而，解决 SiOx 的低电导率、低（初始）库仑效率和表观体积效应仍然是一个巨大的挑战。本文以3-氨丙基三乙氧基硅烷（APTES）为硅源，Co-MOF为钴源，通过分子自组装策略，均匀高效地制备了负载金属Co纳米颗粒的SiOx/Co@C复合阳极材料。实验结果和密度泛函理论（DFT）计算表明，嵌入Co纳米颗粒的催化作用激活了SiOx和不可逆产物Li2O的硅氧键，从而提高了初始库仑效率（ICE）并增强了可逆容量。同时，具有机械刚性和导电性的金属Co缓解了合金化过程中的体积波动，提高了复合材料的电荷传输能力和离子传输速率。与SiOx@C负极相比，SiOx/Co@C-600复合材料表现出更高的初始CE、优异的循环稳定性和良好的倍率性能。特别是，在全电池系统中阳极与磷酸铁锂（LFP）阴极的成功匹配验证了其实际应用的可能性。 该工作为硅基材料在锂离子电池电极材料中的应用以及高能量密度电池的发展提供了重要的见解。