Sequential entrapping of Li and S in a conductivity cage of N-doped reduced graphene oxide supercapacitor derived from silk cocoon: a hybrid Li–S-silk supercapacitor
Li and S compounds are currently exploited for their applications in battery industry. Here, we discovered that Li–S compounds exhibit supercapacitor like properties in a context-dependent manner viz., when Li and S atoms are entrapped in a conductivity cage of N-doped reduced graphene oxide (ND–RGO) supercapacitor derived from silk cocoon, it resulted in the formation of a superior hybrid Li–S-silk (ND–RGO–Li–S) supercapacitor. Interestingly, ND–RGO–Li–S proves to be a better supercapacitor than ND–RGO alone. Electrochemical properties of ND–RGO versus ND–RGO–Li–S indicated that the later has higher capacitance (~ 10.72%), lower resistance (~ 2.98%), and higher time constant or relaxation time (~ 7.52%). Thus, in one of the first attempts, caging Li and S in ND–RGO supercapacitor matrix offers a new role for Li–S, as an improved supercapacitor, unlike its current application as a battery.
KeywordsLithium sulfide Nitrogen-doped reduced graphene oxide Silk cocoon Supercapacitor Li-S-silk supercapacitor Biocharring
This work is part of HJ’s doctoral and pre-doctoral dissertation work. MD would like to thank ISRO, GOI for the financial support. HJ is being supported by MHRD, GOI.
HJ conceived the idea of entrapping the Li and S in an ND–RGO matrix, and synthesized and electrochemically characterized the complex and wrote the manuscript. RJ performed the theoretical and mathematical analysis of the data and wrote the manuscript. SV assisted in structural analysis of the complex. DP helped in optimizing ND–RGO synthesis. SS suggested the idea of wrapping the Li–S complex in carbon matrix and assisted in writing the manuscript. MD laid the overall framework of this study and designed the experiments with HJ and assisted in writing the manuscript.
Compliance with ethical standards
Conflict of interest
All authors declare that there is no competing financial interest in the present work.
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