Lithium-sulfur battery cathodes made of porous biochar support CoFe@NC metal nanoparticles derived from Prussian blue analogues

Abstract

Li–S batteries are considered as candidates for the next-generation secondary batteries due to their high energy density (~ 1672 mAh g−1). However, poor conductivity and shuttle effect have become the major obstacles for their development. In the present investigation, we prepared porous biochar-coated metal nanoparticles CoFe@NC/PPC by loading the Prussian blue analogues onto the biomass pomelo peel (PP), followed by calcination. Both rich nitrogen-doped pore structure and CoFe nanoparticles can reduce the shuttle effect in the cycle, and biochar can enhance the conductivity of the sulfur cathode, promoting the complete reaction of sulfur. It is found that after being sulfur-injected and made into a button cell, it exhibits good electrochemical performance. The initial specific capacity was found to be close to 915.6 mAh g−1 at 1 C and it remained at 447.4 mAh g−1 after 500 cycles with a coulombic efficiency of 97.3%. [Figure not available: see fulltext.] © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.