High Initial Reversible Capacity and Long Life of Ternary SnO₂-Co-carbon Nanocomposite Anodes for Lithium-Ion Batteries.

ABSTRACT: The two major limitations in the application of SnO₂ for lithium-ion battery (LIB) anodes are the large volume variations of SnO₂ 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 SnO₂ 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 SnO₂/Co nanocomposite effectively inhibited Sn coarsening in the lithiated SnO₂ 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.

SUBMITTER: Deng P 

PROVIDER: S-EPMC7770651 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature