Highly interweaved carbonaceous interlayer synchronously decorated by foreign atoms and metals for adsorbing and catalyzing polysulfides in lithium-sulfur batteries

Abstract

A highly interweaved carbonized bacterial cellulose (CBC) decorated by heteroatoms and metallic nanoparticles was fabricated through initial coating of a metallic coordination polymer onto BC nanofibers followed by carbonization. The carbonaceous CBC networks not only efficiently transfer electrons but also entrap the soluble polysulfides by physical interception. Moreover, the polar ingredients of foreign atoms and metals on CBC networks enable a favorable chemisorption toward polysulfides, and meanwhile the embedded metallic nanoparticles promote the conversion kinetics via electrocatalysis. Theoretical simulation and experimental investigation co-confirm that the decorated Ni species greatly enhance the adsorption capability towards polysulfides, as well as reduce the energy barrier of the rate-determining step via electrocatalysis. As a consequence, the lithium-sulfur batteries equipped with the optimal Ni-NCBC interlayer exhibited relatively high specific capacity (1245 mAh g−1 at 0.2 A g−1), superior rate capability (820 mAh g−1 at 4.0 A g−1), and stable cycling performance (73.2 % capacity retention after 1000 cycles). This work proposes a facile strategy to synchronously incorporate heteroatoms and metallic decorations into highly conductive nanofibrous networks for alleviating the shuttling effects of polysulfides effectively.