Yang Jian, Liu Zhigang, Sheng Xiaoxue, Li Jiabao, Wang Tianyi, Wang Chengyin
Institute for Innovative Materials and Energy, Faculty of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City, Jiangsu Province, China.
Institute for Innovative Materials and Energy, Faculty of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou City, Jiangsu Province, China.
J Colloid Interface Sci. 2022 Oct 15;624:40-50. doi: 10.1016/j.jcis.2022.05.090. Epub 2022 May 20.
Tin (Sn)-based electrodes, featuring high electrochemical activity and suitable voltage plateau, gain tremendous attention as promising anode materials for sodium-ion batteries. However, the application of Sn-based electrodes has been largely restricted by the serious pulverization upon repeated cycling due to their large volume expansion, especially at high current densities. Herein, a unique three-dimensional decorated structure was designed, containing ultrafine Sn nanoparticles and nitrogen-deficient carbon nitride (Sn/D-CN), to efficiently alleviate the expansion stress and prevent the aggregation of Sn nanoparticles. Furthermore, the density functional theory calculations have proved the high sodium adsorption ability and improved diffusion kinetics through the hybridization of D-CN with Sn nanoparticles. Further combining the high electronic/ionic conductivity provided by the porous CN matrix, high charge contribution from capacitive behavior, and high sodium storage activity of ultrafine Sn nanoparticles, the resultant Sn/D-CN can achieve an ultrahigh reversible capacity of 518.3 mA g after 300 cycles at 1.0 A g, and even maintaining a reversible capacity of 436.1 mAh g up to 500 cycles (5.0 A g). What's more, the optimized Sn/D-CN∥NaV(PO)/C full cell can keep a high capacity retention of 87.1% at 1.0 A g even after 5000 cycles, manifesting excellent sodium storage performance.
具有高电化学活性和合适电压平台的锡（Sn）基电极，作为钠离子电池有前景的负极材料受到了极大关注。然而，由于Sn基电极在循环过程中因体积大幅膨胀而严重粉化，尤其是在高电流密度下，其应用受到了很大限制。在此，设计了一种独特的三维修饰结构，包含超细Sn纳米颗粒和缺氮氮化碳（Sn/D-CN），以有效缓解膨胀应力并防止Sn纳米颗粒聚集。此外，密度泛函理论计算证明了通过D-CN与Sn纳米颗粒的杂化，其具有高钠吸附能力和改善的扩散动力学。进一步结合多孔CN基体提供的高电子/离子导电性、电容行为的高电荷贡献以及超细Sn纳米颗粒的高储钠活性，所得的Sn/D-CN在1.0 A g下循环300次后可实现518.3 mA g的超高可逆容量，甚至在500次循环（5.0 A g）时仍保持436.1 mAh g的可逆容量。更重要的是，优化后的Sn/D-CN∥NaV(PO)/C全电池即使在5000次循环后，在1.0 A g下仍能保持87.1%的高容量保持率，表现出优异的储钠性能。
