AUTHOR=Jiang Shuli , Huang Ruiming , Zhu Wenchang , Li Xiangyi , Zhao Yue , Gao Zhixiang , Gao Lijun , Zhao Jianqing 

TITLE=Free-Standing SnO2@rGO Anode via the Anti-solvent-assisted Precipitation for Superior Lithium Storage Performance

JOURNAL=Frontiers in Chemistry

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00878

DOI=10.3389/fchem.2019.00878

ISSN=2296-2646

ABSTRACT=<p>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<sub>2</sub>@reduced graphene oxide (SnO<sub>2</sub>@rGO) composite anode, in which SnO<sub>2</sub> nanoparticles are tightly wrapped within wrinkled rGO sheets. The SnO<sub>2</sub>@rGO sheet is assembled in high porosity via an anti-solvent-assisted precipitation of dispersed SnO<sub>2</sub> 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<sub>2</sub>@rGO anode compared with the bare SnO<sub>2</sub> anode material. A high charge capacity above 700 mAh g<sup>−1</sup> can be achieved with a satisfying 95.6% retention after 50 cycles at a current density of 500 mA g<sup>−1</sup>, superior to reserved 126 mAh g<sup>−1</sup> and a much lower 16.8% retention of the bare SnO<sub>2</sub> anode. XRD pattern and HRTEM images of the cycled SnO<sub>2</sub>@rGO anode material verify the expected oxidation of Sn to SnO<sub>2</sub> 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<sub>2</sub>@rGO anode. This work provides a promising SnO<sub>2</sub>-based anode for high-capacity lithium-ion batteries, together with an effective fabrication adoptable to prepare different free-standing composite materials for device applications.</p>