Lithium-sulfur(Li-S)batteries,although a promising candidate of next-generation energy storage devices,are hindered by some bottlenecks in their roadmap toward commercialization.The key challenges include solving the ...Lithium-sulfur(Li-S)batteries,although a promising candidate of next-generation energy storage devices,are hindered by some bottlenecks in their roadmap toward commercialization.The key challenges include solving the issues such as low utilization of active materials,poor cyclic stability,poor rate performance,and unsatisfactory Coulombic efficiency due to the inherent poor electrical and ionic conductivity of sulfur and its discharged products(e.g.,Li2S2 and Li_(2)S),dissolution and migration of polysulfide ions in the electrolyte,unstable solid electrolyte interphase and dendritic growth on an odes,and volume change in both cathodes and anodes.Owing to the high specific surface area,pore volume,low density,good chemical stability,and particularly multimodal pore sizes,hierarchical porous carbon(HPC)mate rials have received considerable attention for circumventing the above pro blems in Li-S batteries.Herein,recent progress made in the synthetic methods and deployment of HPC materials for various components including sulfur cathodes,separators and interlayers,and lithium anodes in Li-S batteries is presented and summarized.More importantly,the correlation between the structures(pore volume,specific surface area,degree of pores,and heteroatom-doping)of HPC and the electrochemical performances of Li-S batteries is elaborated.Finally,a discussion on the challenges and future perspectives associated with HPCs for Li-S batteries is provided.展开更多
In this work,we report a class of wearable,stitchable,and sensitive carbon nanofiber(CNF)-polydimethylsiloxane(PDMS)composite-based piezoresistive sensors realized by carbonizing electrospun polyacrylonitrile(PAN)nano...In this work,we report a class of wearable,stitchable,and sensitive carbon nanofiber(CNF)-polydimethylsiloxane(PDMS)composite-based piezoresistive sensors realized by carbonizing electrospun polyacrylonitrile(PAN)nanofibers and subsequently embedding in PDMS elastomeric thin films.Electro-mechanical tactile sensing characterization of the resulting piezoresistive strain sensors revealed a linear response with an average force sensitivity of~1.82 kN−1 for normal forces up to 20 N.The real-time functionality of the CNF-PDMS composite sensors in wearable body sensor networks and advanced bionic skin applications was demonstrated through human motion and gesture monitoring experiments.A skin-inspired artificial soft sensor capable of demonstrating proprioceptive and tactile sensory perception utilizing CNF bundles has been shown.Furthermore,a 16-point pressure-sensitive flexible sensor array mimicking slow adapting low threshold mechanoreceptors of glabrous skin was demonstrated.Such devices in tandem with neuromorphic circuits can potentially recreate the sense of touch in robotic arms and restore somatosensory perception in amputees.展开更多
This work demonstrates the application of electrospun single and bundled carbon nanofibers(CNFs)as piezoresistive sensing elements in flexible and ultralightweight sensors.Material,electrical,and nanomechanical charac...This work demonstrates the application of electrospun single and bundled carbon nanofibers(CNFs)as piezoresistive sensing elements in flexible and ultralightweight sensors.Material,electrical,and nanomechanical characterizations were conducted on the CNFs to understand the effect of the critical synthesis parameter—the pyrolyzation temperature on the morphological,structural,and electrical properties.The mechanism of conductive path change under the influence of external stress was hypothesized to explain the piezoresistive behavior observed in the CNF bundles.Quasi-static tensile strain characterization of the CNF bundle-based flexible strain sensor showed a linear response with an average gauge factor of 11.14(for tensile strains up to 50%).Furthermore,conductive graphitic domain discontinuity model was invoked to explain the piezoresistivity originating in a single isolated electrospun CNF.Finally,a single piezoresistive CNF was utilized as a sensing element in an NEMS flow sensor to demonstrate air flow sensing in the range of 5-35 m/s.展开更多
基金Yinyu Xiang is very grateful to the China Scholarship Council(CSC:No.201806950083)for his PhD scholarship。
文摘Lithium-sulfur(Li-S)batteries,although a promising candidate of next-generation energy storage devices,are hindered by some bottlenecks in their roadmap toward commercialization.The key challenges include solving the issues such as low utilization of active materials,poor cyclic stability,poor rate performance,and unsatisfactory Coulombic efficiency due to the inherent poor electrical and ionic conductivity of sulfur and its discharged products(e.g.,Li2S2 and Li_(2)S),dissolution and migration of polysulfide ions in the electrolyte,unstable solid electrolyte interphase and dendritic growth on an odes,and volume change in both cathodes and anodes.Owing to the high specific surface area,pore volume,low density,good chemical stability,and particularly multimodal pore sizes,hierarchical porous carbon(HPC)mate rials have received considerable attention for circumventing the above pro blems in Li-S batteries.Herein,recent progress made in the synthetic methods and deployment of HPC materials for various components including sulfur cathodes,separators and interlayers,and lithium anodes in Li-S batteries is presented and summarized.More importantly,the correlation between the structures(pore volume,specific surface area,degree of pores,and heteroatom-doping)of HPC and the electrochemical performances of Li-S batteries is elaborated.Finally,a discussion on the challenges and future perspectives associated with HPCs for Li-S batteries is provided.
基金supported by financial support from the University of Groningen’s start-up grant and Dutch Research Council(NWO)through the NWA Idea Generator project(NWA.1228.192.279)。
文摘In this work,we report a class of wearable,stitchable,and sensitive carbon nanofiber(CNF)-polydimethylsiloxane(PDMS)composite-based piezoresistive sensors realized by carbonizing electrospun polyacrylonitrile(PAN)nanofibers and subsequently embedding in PDMS elastomeric thin films.Electro-mechanical tactile sensing characterization of the resulting piezoresistive strain sensors revealed a linear response with an average force sensitivity of~1.82 kN−1 for normal forces up to 20 N.The real-time functionality of the CNF-PDMS composite sensors in wearable body sensor networks and advanced bionic skin applications was demonstrated through human motion and gesture monitoring experiments.A skin-inspired artificial soft sensor capable of demonstrating proprioceptive and tactile sensory perception utilizing CNF bundles has been shown.Furthermore,a 16-point pressure-sensitive flexible sensor array mimicking slow adapting low threshold mechanoreceptors of glabrous skin was demonstrated.Such devices in tandem with neuromorphic circuits can potentially recreate the sense of touch in robotic arms and restore somatosensory perception in amputees.
文摘This work demonstrates the application of electrospun single and bundled carbon nanofibers(CNFs)as piezoresistive sensing elements in flexible and ultralightweight sensors.Material,electrical,and nanomechanical characterizations were conducted on the CNFs to understand the effect of the critical synthesis parameter—the pyrolyzation temperature on the morphological,structural,and electrical properties.The mechanism of conductive path change under the influence of external stress was hypothesized to explain the piezoresistive behavior observed in the CNF bundles.Quasi-static tensile strain characterization of the CNF bundle-based flexible strain sensor showed a linear response with an average gauge factor of 11.14(for tensile strains up to 50%).Furthermore,conductive graphitic domain discontinuity model was invoked to explain the piezoresistivity originating in a single isolated electrospun CNF.Finally,a single piezoresistive CNF was utilized as a sensing element in an NEMS flow sensor to demonstrate air flow sensing in the range of 5-35 m/s.
