Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properti...Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properties of a carbon-sulfur composite, in which sulfur is impregnated in porous hollow carbon spheres （PHCSs） via a melt-diffusion method. Instrumental analysis shows that the PHCSs, which were prepared by a facile template strategy, are characterized by high specific surface area （1520 m2.g 1）, large pore volume （2.61 cm^3·g^-1）, broad pore size distribution from micropores to mesopores, and high electronic conductivity （2.22 S·cm-1）. The carbon-sulfur composite with a sulfur content of 50.2 wt.% displays an initial discharge capacity of 1450 mA.h·g^-1 （which is 86.6% of the theoretical specific capacity） and a reversible discharge capacity of 1357 mA.h·g^-1 after 50 cycles at 0.05 C charge-discharge rate. At a higher rate of 0.5 C, the capacity stabilized at around 800 mA-h·g^-1 after 30 cycles. The results illustrate that the porous carbon-sulfur composites with hierarchically porous structure have potential application as the cathode of Li-S batteries because of their effective improvement of the electronic conductivity, the repression of the volume expansion, and the reduction of the shuttling loss.展开更多
文摘Carbon-sulfur composites as the cathode of rechargeable Li-S batteries have shown outstanding electrochemical performance for high power devices. Here, we report the promising electrochemical charge-discharge properties of a carbon-sulfur composite, in which sulfur is impregnated in porous hollow carbon spheres （PHCSs） via a melt-diffusion method. Instrumental analysis shows that the PHCSs, which were prepared by a facile template strategy, are characterized by high specific surface area （1520 m2.g 1）, large pore volume （2.61 cm^3·g^-1）, broad pore size distribution from micropores to mesopores, and high electronic conductivity （2.22 S·cm-1）. The carbon-sulfur composite with a sulfur content of 50.2 wt.% displays an initial discharge capacity of 1450 mA.h·g^-1 （which is 86.6% of the theoretical specific capacity） and a reversible discharge capacity of 1357 mA.h·g^-1 after 50 cycles at 0.05 C charge-discharge rate. At a higher rate of 0.5 C, the capacity stabilized at around 800 mA-h·g^-1 after 30 cycles. The results illustrate that the porous carbon-sulfur composites with hierarchically porous structure have potential application as the cathode of Li-S batteries because of their effective improvement of the electronic conductivity, the repression of the volume expansion, and the reduction of the shuttling loss.
