High Initial Reversible Capacity and Long Life of Ternary SnO(2)-Co-carbon Nanocomposite Anodes for Lithium-Ion Batteries

The two major limitations in the application of SnO(2) for lithium-ion battery (LIB) anodes are the large volume variations of SnO(2) during repeated lithiation/delithiation processes and a large irreversible capacity loss during the first cycle, which can lead to a rapid capacity fade and unsatisfactory initial Coulombic efficiency (ICE). To overcome these limitations, we developed composites of ultrafine SnO(2) nanoparticles and in situ formed Co(CoSn) nanocrystals embedded in an N-doped carbon matrix using a Co-based metal–organic framework (ZIF-67). The formed Co additives and structural advantages of the carbon-confined SnO(2)/Co nanocomposite effectively inhibited Sn coarsening in the lithiated SnO(2) and mitigated its structural degradation while facilitating fast electronic transport and facile ionic diffusion. As a result, the electrodes demonstrated high ICE (82.2%), outstanding rate capability (~ 800 mAh g(−1) at a high current density of 5 A g(−1)), and long-term cycling stability (~ 760 mAh g(−1) after 400 cycles at a current density of 0.5 A g(−1)). This study will be helpful in developing high-performance Si (Sn)-based oxide, Sn/Sb-based sulfide, or selenide electrodes for LIBs. In addition, some metal organic frameworks similar to ZIF-67 can also be used as composite templates. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40820-019-0246-4) contains supplementary material, which is available to authorized users.