A highly flexible and continuous fibrous thermoelectric(TE)module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber,which effectively avoids the drawbacks of traditio...A highly flexible and continuous fibrous thermoelectric(TE)module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber,which effectively avoids the drawbacks of traditional inorganic TE based modules.The maximum output power density of a 1-cm long fibrous TE module with 8 p–n pairs can reach to 3436μW·cm^(-2),the power per unit weight to 2034μW·g^(-1),at a steady-state temperature difference of 50 K.The continuous fibrous TE module is used to detect temperature change of a single point,which exhibits a good responsiveness and excellent stability.Because of its adjustability in length,the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy.Based on the signal of the as-fabricated TE module,a multi-region recognizer has been designed and demonstrated.The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation,temperature detection,and position identification.展开更多
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an...Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.展开更多
Solar cells that combine single-crystalline silicon （Si） with graphene （G） have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency （PCE） of ...Solar cells that combine single-crystalline silicon （Si） with graphene （G） have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency （PCE） of G/Si solar cell without chemical doping is commonly low due to the relatively high resistance of graphene. In this work, through combining graphene with carbon nanotube （CNT） networks, we fabricated three kinds of hybrid nanocarbon film/Si heterojunction solar cells in order to increase the PCE of the graphene based Si solar cell. We investigated the characteristics of different nanocarbon film/Si solar cells and found that their performance depends on the heterojunctions. Specifically, a doping-free G-CNT/Si solar cell demonstrated a high PCE of 7.9%, which is nearly equal to the combined value of two individuals （G/Si and CNT/Si）. This high efficiency is attributed to the synergistic effect of graphene and CNTs, and can be further increased to 9.1% after applying a PMMA antireflection coating. This study provides a potential way to further improve the Si based heterojunction solar cells.展开更多
Lithium–sulfur（Li–S） batteries have received more and more attention because of higher specific capacity and energy density of sulfur than current lithium–ion batteries. However, the low electrical conductivity o...Lithium–sulfur（Li–S） batteries have received more and more attention because of higher specific capacity and energy density of sulfur than current lithium–ion batteries. However, the low electrical conductivity of sulfur and its discharge product, and also the high dissolution of polysulfides restrict the Li–S battery practical applications. To improve their performances, in this work, we fabricate a novel free-standing, curled and partially reduced graphene oxide（CPrGO for short） network and combine it with sulfur to form a CPrGO–S composite as a cathode for Li–S battery. With sulfur content of 60 wt%, the free-standing CPrGO–S composite network delievers an initial capacity of 988.9 m Ah·g^（-1）. After 200 cycles,it shows a stable capacity of 841.4 m Ah·g^（-1） at 0.2 C, retaining about 85% of the initial value. The high electrochemical performance demonstrates that the CPrGO–S network has great potential applications in energy storage system. Such improved properties can be ascribed to the unique free-standing and continous CPrGO–S network which has high specific surface area and good electrical conductivity. In addition, oxygen-containing groups on the partially reduced graphene oxide are beneficial to preventing the polysulfides from dissolving into electrolyte and can mitigate the ＂shuttle effect＂.展开更多
基金the National Key Research and Development Program of China(Grant No.2018YFA0208402)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,and 51372269)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040202)。
文摘A highly flexible and continuous fibrous thermoelectric(TE)module with high-performance has been fabricated based on an ultra-long single-walled carbon nanotube fiber,which effectively avoids the drawbacks of traditional inorganic TE based modules.The maximum output power density of a 1-cm long fibrous TE module with 8 p–n pairs can reach to 3436μW·cm^(-2),the power per unit weight to 2034μW·g^(-1),at a steady-state temperature difference of 50 K.The continuous fibrous TE module is used to detect temperature change of a single point,which exhibits a good responsiveness and excellent stability.Because of its adjustability in length,the flexible fibrous TE module can satisfy the transformation of the temperature difference between two distant heat sources into electrical energy.Based on the signal of the as-fabricated TE module,a multi-region recognizer has been designed and demonstrated.The highly flexible and continuous fibrous TE module with excellent performance shows a great potential in diversified applications of TE generation,temperature detection,and position identification.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,51372269,and 51472264)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0208402)the National Basic Research Program of China(Grant No.2012CB932302)+1 种基金the National Natural Science Foundation of China(Grant Nos.11634014,51172271,and 51372269)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Solar cells that combine single-crystalline silicon （Si） with graphene （G） have been widely researched in order to develop next-generation photovoltaic devices. However, the power conversion efficiency （PCE） of G/Si solar cell without chemical doping is commonly low due to the relatively high resistance of graphene. In this work, through combining graphene with carbon nanotube （CNT） networks, we fabricated three kinds of hybrid nanocarbon film/Si heterojunction solar cells in order to increase the PCE of the graphene based Si solar cell. We investigated the characteristics of different nanocarbon film/Si solar cells and found that their performance depends on the heterojunctions. Specifically, a doping-free G-CNT/Si solar cell demonstrated a high PCE of 7.9%, which is nearly equal to the combined value of two individuals （G/Si and CNT/Si）. This high efficiency is attributed to the synergistic effect of graphene and CNTs, and can be further increased to 9.1% after applying a PMMA antireflection coating. This study provides a potential way to further improve the Si based heterojunction solar cells.
基金supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,and 51372269)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Lithium–sulfur（Li–S） batteries have received more and more attention because of higher specific capacity and energy density of sulfur than current lithium–ion batteries. However, the low electrical conductivity of sulfur and its discharge product, and also the high dissolution of polysulfides restrict the Li–S battery practical applications. To improve their performances, in this work, we fabricate a novel free-standing, curled and partially reduced graphene oxide（CPrGO for short） network and combine it with sulfur to form a CPrGO–S composite as a cathode for Li–S battery. With sulfur content of 60 wt%, the free-standing CPrGO–S composite network delievers an initial capacity of 988.9 m Ah·g^（-1）. After 200 cycles,it shows a stable capacity of 841.4 m Ah·g^（-1） at 0.2 C, retaining about 85% of the initial value. The high electrochemical performance demonstrates that the CPrGO–S network has great potential applications in energy storage system. Such improved properties can be ascribed to the unique free-standing and continous CPrGO–S network which has high specific surface area and good electrical conductivity. In addition, oxygen-containing groups on the partially reduced graphene oxide are beneficial to preventing the polysulfides from dissolving into electrolyte and can mitigate the ＂shuttle effect＂.
