Jiang Shuli, Huang Ruiming, Zhu Wenchang, Li Xiangyi, Zhao Yue, Gao Zhixiang, Gao Lijun, Zhao Jianqing
College of Energy, Soochow Institute for Energy and Materials Innovations, Soochow University, Suzhou, China.
Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, China.
Front Chem. 2019 Dec 19;7:878. doi: 10.3389/fchem.2019.00878. eCollection 2019.
Metal oxides have been attractive as high-capacity anode materials for lithium-ion batteries. However, oxide anodes encounter drastic volumetric changes during lithium ion storage through the conversion reaction and alloying/dealloying processes, leading to rapid capacity decay and poor cycling stability. Here, we report a free-standing SnO@reduced graphene oxide (SnO@rGO) composite anode, in which SnO nanoparticles are tightly wrapped within wrinkled rGO sheets. The SnO@rGO sheet is assembled in high porosity via an anti-solvent-assisted precipitation of dispersed SnO nanoparticles and graphene oxide sheets in the distilled water, followed by the filtration and post-annealing processes. Significantly enhanced lithium storage performance has been obtained of the SnO@rGO anode compared with the bare SnO anode material. A high charge capacity above 700 mAh g can be achieved with a satisfying 95.6% retention after 50 cycles at a current density of 500 mA g, superior to reserved 126 mAh g and a much lower 16.8% retention of the bare SnO anode. XRD pattern and HRTEM images of the cycled SnO@rGO anode material verify the expected oxidation of Sn to SnO at the fully-charged state in the 50th cycle. In addition, FESEM and TEM images reveal the well-preserved free-standing structure after cycling, which accounts for high reversible capacity and excellent cycling stability of such a SnO@rGO anode. This work provides a promising SnO-based anode for high-capacity lithium-ion batteries, together with an effective fabrication adoptable to prepare different free-standing composite materials for device applications.
金属氧化物作为锂离子电池的高容量负极材料一直备受关注。然而，氧化物负极在锂离子存储过程中，通过转化反应和合金化/脱合金化过程会发生剧烈的体积变化，导致容量迅速衰减和循环稳定性差。在此，我们报道了一种独立的SnO@还原氧化石墨烯（SnO@rGO）复合负极，其中SnO纳米颗粒被紧密包裹在褶皱的rGO片层中。SnO@rGO片层通过在蒸馏水中分散的SnO纳米颗粒和氧化石墨烯片层的反溶剂辅助沉淀，然后经过过滤和后退火工艺，以高孔隙率组装而成。与裸SnO负极材料相比，SnO@rGO负极的锂存储性能得到了显著提高。在500 mA g的电流密度下循环50次后，可实现高于700 mAh g的高充电容量，保留率为95.6%，优于裸SnO负极保留的126 mAh g和低得多的16.8%的保留率。循环后的SnO@rGO负极材料的XRD图谱和HRTEM图像验证了在第50次循环的完全充电状态下Sn氧化为SnO的预期结果。此外，FESEM和TEM图像显示循环后独立结构保存完好，这解释了这种SnO@rGO负极具有高可逆容量和优异的循环稳定性。这项工作为高容量锂离子电池提供了一种有前景的基于SnO的负极，同时提供了一种可有效制备用于器件应用的不同独立复合材料的制备方法。
