Xie Mengna, Zhou Yongheng, Dong Shuai, Li Fei, Zhang Fenghua, Wei Wei, Cui Jinhai
School of Petrochemical Engineering, Liaoning Petrochemical University Fushun 113001 P. R. China
Henan Engineering Center of New Energy Battery Materials, School of Chemistry and Chemical Engineering, Shangqiu Normal University Shangqiu 476000 P. R. China
RSC Adv. 2025 Jun 6;15(24):19176-19191. doi: 10.1039/d5ra02378e. eCollection 2025 Jun 4.
Lower lithium-ion diffusion rates and significant volumetric expansion present serious challenges for using SnO/SnO composites as promising anode materials in advanced lithium-ion batteries. To address this issue, we synthesized a novel Sn@C/CNT composite from a Sn-based organometallic complex with 2-methylimidazole and oxidized multi-wall carbon nanotubes. Structural analysis has confirmed that the tin-based composites consist of nano-lamellar assemblies modified by oxidized carbon nanotubes. In these composites, the tin active particles have an average size ranging from 2 to 3 nm, while the layered nano-lamellar structure has an average thickness of 6 nm. The resulting Sn@C/CNT anode material demonstrated a stable specific capacity of up to 688 mA h g even after 500 cycles at a higher charging-discharging current density of 1 A g. The significant diffusion-controlled lithium ion diffusion coefficient of approximately 10 cm s indicates vigorous dynamic activity from reversible Sn-Li alloy electrochemical reactions. Additionally, the substantial capacity-controlled lithium ion diffusion coefficient, which drops to 10 cm s, illustrates the predominance of the pseudo-capacitance arising from interface reaction. By coupling electrochemical impedance spectroscopy, galvanostatic intermittent titration technique, and linear sweep voltammetry, the mixed lithium-ion diffusion effect was proposed to explain the remarkable adaptability of these Sn-based anode materials for cycling performance across a wide range of specific currents. This work provides a new intention for resolving the drastic volumetric expansion and unsatisfactory dynamic activity of Sn-based anode materials.
较低的锂离子扩散速率和显著的体积膨胀给将SnO/SnO复合材料用作先进锂离子电池中有前景的负极材料带来了严峻挑战。为了解决这个问题，我们用一种基于Sn的有机金属配合物与2-甲基咪唑和氧化多壁碳纳米管合成了一种新型的Sn@C/CNT复合材料。结构分析证实，锡基复合材料由被氧化碳纳米管修饰的纳米层状组装体组成。在这些复合材料中，锡活性颗粒的平均尺寸在2到3纳米之间，而层状纳米层结构的平均厚度为6纳米。所得的Sn@C/CNT负极材料即使在1 A g的较高充放电电流密度下循环500次后仍表现出高达688 mA h g的稳定比容量。约10 cm s的显著扩散控制锂离子扩散系数表明可逆的Sn-Li合金电化学反应具有活跃的动力学活性。此外，降至10 cm s的大量容量控制锂离子扩散系数说明了界面反应产生的赝电容的主导地位。通过结合电化学阻抗谱、恒电流间歇滴定技术和线性扫描伏安法，提出了混合锂离子扩散效应来解释这些锡基负极材料在宽范围特定电流下对循环性能的显著适应性。这项工作为解决锡基负极材料剧烈的体积膨胀和不令人满意的动力学活性提供了新的思路。
