Fabricating ultrathin ZrB2/Graphene oxide/carboxymethocel layer onto cathode as effective polysulfide shuttling barrier for Li–S battery

The shuttling effect of soluble polysulfide in electrolyte has been the major obstacle resulting in the poor cycling stability of Li–S battery. The ultrathin ZrB2/graphene oxide/carboxymethocel (ZrB2/GO/CMC) layer coated onto cathode via simple doctor blade method has been developed as the effective polysulfide shuttling barrier. Owing to typical 2D scaffold and abundant functional oxygen groups，the GO can provide physical defender as well as chemical trap against polysulfide shuttling. The introduction of conductive ZrB2 nanoparticles in the hybrid layer can not only improve the conductivity of hybrid layer dramatically reducing electrochemical polarization of Li–S battery without adding other conductive agent but also further form chemical shield by chemisorption which is firstly confirmed by experimental and theoretical calculations. Combining these merits, the ultrathin ZrB2/GO/CMC hybrid layer combining with CNT@S hybrid cathode enables the Li–S battery to achieve good rate performance (769 mAh g−1 at a rate of 2 C) and stable cycling capability (with a low capacity decay rate of 0.098% during 300 cycles at 1 C). Specifically, the Li–S battery shows the potential of practical application, with high areal S loading of 5.1 mg cm−2, delivering the capacity near-commercial lithium-ion battery.