Lithium–sulfur(Li–S)batteries can potentially outperform state-of-the-art lithium-ion batteries,but their further development is hindered by challenges,such as poor electrical conductivity of sulfur and lithium sulf...Lithium–sulfur(Li–S)batteries can potentially outperform state-of-the-art lithium-ion batteries,but their further development is hindered by challenges,such as poor electrical conductivity of sulfur and lithium sulfide,shuttle phenomena of lithium polysulfides,and uneven distribution of solid reaction products.Herein,free-standing carbon nanofibers embedded with oxygen-deficient titanium dioxide nanoparticles(TiO_(2-x)/CNFs)has been fabricated by a facile electrospinning method,which can support active electrode materials without the need for conductive carbon and binders.By carefully controlling the calcination temperature,a mixed phase of rutile and anatase was achieved in the TiO_(2-x)nanoparticles.The hybridization of anatase/rutile TiO_(2-x)and the oxygen vacancy in TiO_(2-x)play a crucial role in enhancing the conversion kinetics of lithium polysulfides(LiPSs),mitigating the shuttle effect of LiPSs,and enhancing the overall efficiency of the Li–S battery system.Additionally,the free-standing TiO_(2-x)/CNFs facilitate uniform deposition of reaction products during cycling,as confirmed by synchrotron X-ray imaging.As a result of these advantageous features,the TiO_(2-x)/CNFs-based cathode demonstrates an initial specific discharge capacity of 787.4 mAh g^(−1)at 0.5 C in the Li–S coin cells,and a final specific discharge capacity of 584.0 mAh g^(−1) after 300 cycles.Furthermore,soft-packaged Li–S pouch cells were constructed using the TiO_(2-x)/CNFs-based cathode,exhibiting excellent mechanical properties at different bending states.This study presents an innovative approach to developing free-standing sulfur host materials that are well suited for flexible Li–S batteries as well as for various other energy applications.展开更多
基金funding enabled and organized by Projekt DEAL.This article is funded by China Scholarship Council,202006630007Ping Feng,State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,LK1702。
文摘Lithium–sulfur(Li–S)batteries can potentially outperform state-of-the-art lithium-ion batteries,but their further development is hindered by challenges,such as poor electrical conductivity of sulfur and lithium sulfide,shuttle phenomena of lithium polysulfides,and uneven distribution of solid reaction products.Herein,free-standing carbon nanofibers embedded with oxygen-deficient titanium dioxide nanoparticles(TiO_(2-x)/CNFs)has been fabricated by a facile electrospinning method,which can support active electrode materials without the need for conductive carbon and binders.By carefully controlling the calcination temperature,a mixed phase of rutile and anatase was achieved in the TiO_(2-x)nanoparticles.The hybridization of anatase/rutile TiO_(2-x)and the oxygen vacancy in TiO_(2-x)play a crucial role in enhancing the conversion kinetics of lithium polysulfides(LiPSs),mitigating the shuttle effect of LiPSs,and enhancing the overall efficiency of the Li–S battery system.Additionally,the free-standing TiO_(2-x)/CNFs facilitate uniform deposition of reaction products during cycling,as confirmed by synchrotron X-ray imaging.As a result of these advantageous features,the TiO_(2-x)/CNFs-based cathode demonstrates an initial specific discharge capacity of 787.4 mAh g^(−1)at 0.5 C in the Li–S coin cells,and a final specific discharge capacity of 584.0 mAh g^(−1) after 300 cycles.Furthermore,soft-packaged Li–S pouch cells were constructed using the TiO_(2-x)/CNFs-based cathode,exhibiting excellent mechanical properties at different bending states.This study presents an innovative approach to developing free-standing sulfur host materials that are well suited for flexible Li–S batteries as well as for various other energy applications.
