Improved electrochemical performances of sulfur-microporous carbon composite electrode for Li/S battery

A sulfur-microporous (S-MIP) carbon composite was prepared for use as a cathode for rechargeable Li/S batteries. Two sulfur-embedded methods, S-impregnation (IS) and S-liquefied pore filling (LS), were applied for the preparation of the S-MIP carbon composites. The pristine elemental S of the polycrystalline alpha-S-8 undergoes a structural change to an amorphous-S (a-S) structure in the S-MIP carbon composite created by the IS method. During sulfur loading of 40-50 wt %, the S-MIP carbon composite created by the IS method showed a BET SSA value of around 500 m(2) g(-1) and a pore volume of 0.2 cm(3) g(-1). However, after the LS process was applied to the S-MIP carbon composite, at 160 A degrees C and 10 h, the a-S structure in the S-MIP carbon composite became recrystalline alpha-S-8. Little remained of the porosity in the S-MIP carbon composite prepared by the LS method due to the large portion of the S crystalline phase. The best discharge capacity was obtained with an S-MIP carbon composite created by the IS method, with the result of 680 mA h g(-1) after 50 cycles at 0.1 A degrees C, i.e., similar to 47 % higher than that by the LS method.