Nitrogen-doped porous hollow carbon sphere-decorated separators enhance performance of Li-S batteries
Researchers from Central South University in Changsha, China, have developed a separator with a nitrogen-doped porous hollow carbon sphere (NHC) coating for use in Li-S batteries. The NHC-decorated separator enormously improves the utilization of active material and enhances electrochemical performance.
They prepared the nitrogen-doped porous hollow carbon spheres by pyrolysis of a polydopamine (PDA) carbon precursor on the surface of silicon dioxide (SiO2). The resulting NHCs are coated onto one side of the separator using a slurry-coating method.
In a paper in Journal of Power Sources, they reported achieving an initial discharge capacity of 1656 mAh g−1 (0.2 C) and a low capacity fading rate of 0.11% per cycle within 500 cycles (1 C). They attributed this performance to the high specific surface area and pore volume of the NHCs which ensure electrolyte infiltration and act as a barrier for polysulfides. Furthermore, the high nitrogen content in NHCs can improve electronic conductivity and enhance interaction between nitrogen atoms and polysulfides.
The NHC-decorated separator is of low cost and can effectively improve energy density of Li–S cells, exhibiting potential for further development of Li–S batteries.
Zhian Zhang, Guanchao Wang, Yanqing Lai, Jie Li, Zhiyong Zhang, Wei Chen (2015) “Nitrogen-doped porous hollow carbon sphere-decorated separators for advanced lithium–sulfur batteries,” Journal of Power Sources, Volume 300, Pages 157-163 doi: 10.1016/j.jpowsour.2015.09.067