Confined selenium within metal-organic frameworks derived porous carbon microcubes as cathode for rechargeable lithium-selenium batteries

Unique hierarchically porous carbon microcubes (CMCs) consists of irregular bubbles derived from metal organic frameworks (MOFs) have been prepared via simple hydrothermal synthesis method and carbonization treatment. Selenium nanoparticles are uniformly dispersed in the hierarchical porous structure of CMCs by a typical melt-diffusion process, and the yielding Se/CMCs composite is enabled as a cathode material for lithium-selenium rechargeable batteries. In the carbonate-based electrolyte, with Se loading of nearly ∼50 wt%, the Se/CMCs composite exhibits an ultrahigh initial discharge specific capacity of 780.4 mAh g−1 and still retains a reversible capacity of 425.2 mAh g−1 after 100 cycles at 0.2 C. Specially, these hollow structure CMCs with high conductivity contribute to the outstanding electrochemical properties by effectively decreasing the charge transfer resistance and suppressing polyselenides dissolution in carbonate electrolyte.