Metal-organic frameworks-derived mesoporous carbon for high performance lithium–selenium battery

Selenium was confined in mesoporous carbon matrix derived from porous metal-organic frameworks (meso-Ce) as cathode material for lithium-selenium rechargeable batteries. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetry (TG) measurements. It is found that the selenium was dispersed inside the pores of carbon materials. The electrochemical performance of meso-Ce cathode was tested by cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy. It is found that meso-Ce cathode has great cycling stability, Coulombic efficiency and high rate performance. The meso-Ce composite with selenium content of 48 wt% displays an initial discharge capacity of 641 mAh g super(-1) and a reversible capacity of 306.9 mAh g super(-1) after 100 cycles at a current density of 337.5 mA g super(-1) (0.5 C). Particularly, the meso-Ce cathode displays the initial discharge capacity and 100th cycle reversible capacity of 659.9 and 279.5 mAh g super(-1) at 2 C, showing great high-rate performance. These favourable performance should attribute to the high conductivity of carbon matrix significantly decreases its charge transfer resistance and effectively suppresses the shuttle effect of polyselenides from the composite cathode.