In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The mat...In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.展开更多
Room-temperature sodium–sulfur(RT/Na–S)batteries are regarded as promising large-scale stationary energy storage systems owing to their high energy density and low cost as well as the earth-abundant reserves of sodi...Room-temperature sodium–sulfur(RT/Na–S)batteries are regarded as promising large-scale stationary energy storage systems owing to their high energy density and low cost as well as the earth-abundant reserves of sodium and sulfur.However,the diffusion of polysulfides and sluggish kinetics of conversion reactions are still major challenges for their application.Herein,we developed a powerful and functional separator to inhibit the shuttle effect by coating a lightweight three-dimensional cellulose nanofiber-derived carbon aerogel on a glass fiber separator(denoted NSCA@GF).The hierarchical porous structures,favorable electronic conductivity,and three-dimensional interconnected network of N,S-codoped carbon aerogel endow a multifunctional separator with strong polysulfide anchoring capability and fast reaction kinetics of polysulfide conversion,which can act as the barrier layer and an expanded current collector to increase sulfur utilization.Moreover,the hetero-doped N/S sites are believed to strengthen polysulfide anchoring capability via chemisorption and accelerate the redox kinetics of polysulfide conversion,which is confirmed from experimental and theoretical results.As a result,the assembled Na–S coin cells with the NSCA@GF separator showed a high reversible capacity(788.8 mAh g^(−1) at 0.1 C after 100 cycles)and superior cycling stability(only 0.059%capacity decay per cycle over 1000 cycles at 1 C),thereby demonstrating the significant potential for application in high-performance RT/Na–S batteries.展开更多
Two-dimensional(2 D) graphene oxide(GO) nanosheets and 1 D2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO)-oxidized cellulose nanofibers(TOCN) were assembled into GO/TOCN aerogels via a low temperature hydrothermal and free...Two-dimensional(2 D) graphene oxide(GO) nanosheets and 1 D2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO)-oxidized cellulose nanofibers(TOCN) were assembled into GO/TOCN aerogels via a low temperature hydrothermal and freeze-drying process. The as-prepared GO/TOCN aerogels exhibited interconnected 3 D network microstructures, a low density of 6.8 mg/cm^3, a high porosity up to 99.2% and excellent mechanical flexibility.The high porosity in conjunction with their hydrophobicity(contact angle of 121.5°), allowed the aerogels to absorb different organic liquids with absorption capacities up to 240 times of their own weight, depending on the density of the liquids. These results indicated that the aerogels were excellent candidates as sorbent materials for the clean-up of organic liquids. After five absorption-desorption cycles, the absorption capacity of the TOCN carbon aerogels could be regenerated up to 97% of the initial absorption capability,which demonstrated their excellent recyclability.展开更多
Cellulose has a wide range of applications in many fields due to their naturally degradable and low-cost characteristics,but few studies can achieve cellulose-nanofibers by conventional electrospinning.Herein,we demon...Cellulose has a wide range of applications in many fields due to their naturally degradable and low-cost characteristics,but few studies can achieve cellulose-nanofibers by conventional electrospinning.Herein,we demonstrate that the freestanding cellulose-based carbon nanofibers are successfully obtained by a special design of electrospinning firstly,pre-oxidation and high-temperature carbonization(1600℃),which display a superior electrical conductivity of 31.2 S·cm^(-1)and larger specific surface area of 35.61 m^(2)·g^(-1)than that of the polyacrylonitrile-based carbon nanofibers(electrical conductivity of 18.5 S·cm^(-1),specific surface area of 12 m^(2)·g^(-1).The NiCo_(2)O_(4)nanoflake arrays are grown uniformly on the cellulose-based carbon nanofibers successfully by a facile one-step solvothermal and calcination method.The as-prepared cellulose-based carbon nanofibers/NiCo_(2)O_(4)nanoflake arrays are directly used as electrodes to achieve a high specific capacitance of 1010 F·g^(-1)at 1 A·g^(-1)and a good cycling stability with 90.84%capacitance retention after 3000 times at 10 A·g^(-1).Furthermore,the all-solid-state symmetric supercapacitors assembled from the cellulose-based carbon nanofibers/NiCo_(2)O_(4)deliver a high energy density of 62 W·h·kg(-1) at a power density of 1200 W·kg^(-1).Six all-solid-state symmetric supercapacitors in series can also power a‘DHU’logo consisted of 36 light emitting diodes,confirming that the cellulose-based carbon nanofiber is a promising carbon matrix material for energy storage devices.展开更多
Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress ...Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress transfer and thus the fabrication of flexible carbon aerogel from renewable nano building blocks.Herein,a structural defect-reducing strategy is proposed by altering the pyrolysis route of cellulose nanofiber.Inorganic salt that inhibits the generation of tar volatilization during pyrolysis can prevent the formation of various structural defects.Microstructure with fewer defects can reduce stress concentration and remarkably enhance the compressibility of carbon aerogel,thus increasing the maximum stress retention of carbon aerogel.The carbon aerogel also has high stress sensor sensitivity and excellent temperature coefficient of resistance.The structural defect-reducing strategy will pave a new way to fabricate high-strength carbon materials for various fields.展开更多
目的以竹粉为原料制备纳米纤维素,并将其作为基底材料制备纳米纤维素/碳纳米管/纳米银线复合电极,应用于柔性超级电容器。方法采用化学机械处理法,将竹粉通过化学处理以及研磨、超声等处理,制备成纳米纤维素悬浮液;分别将多壁碳纳米管...目的以竹粉为原料制备纳米纤维素,并将其作为基底材料制备纳米纤维素/碳纳米管/纳米银线复合电极,应用于柔性超级电容器。方法采用化学机械处理法,将竹粉通过化学处理以及研磨、超声等处理,制备成纳米纤维素悬浮液;分别将多壁碳纳米管和纳米银线超声分散于溶剂中;最后,通过层层自组装制备纳米纤维素/碳纳米管/纳米银线复合电极,同时,作为对照组,制备纳米纤维素/碳纳米管复合电极。结果纳米纤维素纤丝的直径大约为30~100 nm,相互之间缠绕成网状结构,是很好的支撑材料,纳米纤维素/碳纳米管/纳米银线复合电极具有很好的成膜性和电化学性能,在扫描速率为30 m V/s时,面积比电容达到77.95 m F/cm^2。结论以纳米纤维素为基底,通过层层自组装方法制备的纳米纤维素/碳纳米管/纳米银线复合电极具有较好的电化学性能,可作为柔性超级电容器的电极。展开更多
基金financial support from the following sources: the National Natural Science Foundation of China (NSFC) (Grants 51607054, 51772073)Young Talent of Hebei Province (Nos. 70280011808, 70280016160250)+1 种基金Hebei Province Outstanding Youth Fund (A2018201019, A2017201082)Hebei Province Natural Science Fund (A2015201050)。
文摘In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.
基金support of the Guangdong Basic and Applied Basic Research Foundation(grant nos.2020A1515110705 and 2021A1515110245)the China Postdoctoral Science Foundation(grant nos.2020M682711 and 2020M682710)+2 种基金the National Program for Support of Topnotch Young Professionals(grant no.x2qsA4210090)the National Natural Science Foundation of China(grant no.31971614)the State Key Laboratory of Pulp and Paper Engineering(grant no.2020C03).
文摘Room-temperature sodium–sulfur(RT/Na–S)batteries are regarded as promising large-scale stationary energy storage systems owing to their high energy density and low cost as well as the earth-abundant reserves of sodium and sulfur.However,the diffusion of polysulfides and sluggish kinetics of conversion reactions are still major challenges for their application.Herein,we developed a powerful and functional separator to inhibit the shuttle effect by coating a lightweight three-dimensional cellulose nanofiber-derived carbon aerogel on a glass fiber separator(denoted NSCA@GF).The hierarchical porous structures,favorable electronic conductivity,and three-dimensional interconnected network of N,S-codoped carbon aerogel endow a multifunctional separator with strong polysulfide anchoring capability and fast reaction kinetics of polysulfide conversion,which can act as the barrier layer and an expanded current collector to increase sulfur utilization.Moreover,the hetero-doped N/S sites are believed to strengthen polysulfide anchoring capability via chemisorption and accelerate the redox kinetics of polysulfide conversion,which is confirmed from experimental and theoretical results.As a result,the assembled Na–S coin cells with the NSCA@GF separator showed a high reversible capacity(788.8 mAh g^(−1) at 0.1 C after 100 cycles)and superior cycling stability(only 0.059%capacity decay per cycle over 1000 cycles at 1 C),thereby demonstrating the significant potential for application in high-performance RT/Na–S batteries.
基金supported by the State Key Laboratory of Pulp and Paper Engineering (201750)Chinese Ministry of Education (113014A)National Natural Science Foundation of China (21404011, 21674013)
文摘Two-dimensional(2 D) graphene oxide(GO) nanosheets and 1 D2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO)-oxidized cellulose nanofibers(TOCN) were assembled into GO/TOCN aerogels via a low temperature hydrothermal and freeze-drying process. The as-prepared GO/TOCN aerogels exhibited interconnected 3 D network microstructures, a low density of 6.8 mg/cm^3, a high porosity up to 99.2% and excellent mechanical flexibility.The high porosity in conjunction with their hydrophobicity(contact angle of 121.5°), allowed the aerogels to absorb different organic liquids with absorption capacities up to 240 times of their own weight, depending on the density of the liquids. These results indicated that the aerogels were excellent candidates as sorbent materials for the clean-up of organic liquids. After five absorption-desorption cycles, the absorption capacity of the TOCN carbon aerogels could be regenerated up to 97% of the initial absorption capability,which demonstrated their excellent recyclability.
基金supported by Key Support Project of State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(Grant No.21M1060212)Open Project of Shanghai Key Laboratory of Lightweight Structural Composite Materials(Grant No.2232019A4-02)+1 种基金National Natural Science Foundation of China(Grant No.51503086)the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(Grant No.CUSF-DH-D-2022013).
文摘Cellulose has a wide range of applications in many fields due to their naturally degradable and low-cost characteristics,but few studies can achieve cellulose-nanofibers by conventional electrospinning.Herein,we demonstrate that the freestanding cellulose-based carbon nanofibers are successfully obtained by a special design of electrospinning firstly,pre-oxidation and high-temperature carbonization(1600℃),which display a superior electrical conductivity of 31.2 S·cm^(-1)and larger specific surface area of 35.61 m^(2)·g^(-1)than that of the polyacrylonitrile-based carbon nanofibers(electrical conductivity of 18.5 S·cm^(-1),specific surface area of 12 m^(2)·g^(-1).The NiCo_(2)O_(4)nanoflake arrays are grown uniformly on the cellulose-based carbon nanofibers successfully by a facile one-step solvothermal and calcination method.The as-prepared cellulose-based carbon nanofibers/NiCo_(2)O_(4)nanoflake arrays are directly used as electrodes to achieve a high specific capacitance of 1010 F·g^(-1)at 1 A·g^(-1)and a good cycling stability with 90.84%capacitance retention after 3000 times at 10 A·g^(-1).Furthermore,the all-solid-state symmetric supercapacitors assembled from the cellulose-based carbon nanofibers/NiCo_(2)O_(4)deliver a high energy density of 62 W·h·kg(-1) at a power density of 1200 W·kg^(-1).Six all-solid-state symmetric supercapacitors in series can also power a‘DHU’logo consisted of 36 light emitting diodes,confirming that the cellulose-based carbon nanofiber is a promising carbon matrix material for energy storage devices.
基金the National Natural Science Foundation of China(Nos.32201499,22208069 and 32071714)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110205)+1 种基金Fundamental Research Funds for the Central Universities(No.2022ZYGXZR019)the State Key Laboratory of Pulp&Paper Engineering(No.2022C01).
文摘Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress transfer and thus the fabrication of flexible carbon aerogel from renewable nano building blocks.Herein,a structural defect-reducing strategy is proposed by altering the pyrolysis route of cellulose nanofiber.Inorganic salt that inhibits the generation of tar volatilization during pyrolysis can prevent the formation of various structural defects.Microstructure with fewer defects can reduce stress concentration and remarkably enhance the compressibility of carbon aerogel,thus increasing the maximum stress retention of carbon aerogel.The carbon aerogel also has high stress sensor sensitivity and excellent temperature coefficient of resistance.The structural defect-reducing strategy will pave a new way to fabricate high-strength carbon materials for various fields.
基金supported by the Hundred Talents Program of Chinese Academy of Sciencesthe National Basic Research Program of China (973 Program, 2014CB932300, 2012CB215500)the National Natural Science Foundation of China (20921002, 21101147, 21203176)~~
文摘目的以竹粉为原料制备纳米纤维素,并将其作为基底材料制备纳米纤维素/碳纳米管/纳米银线复合电极,应用于柔性超级电容器。方法采用化学机械处理法,将竹粉通过化学处理以及研磨、超声等处理,制备成纳米纤维素悬浮液;分别将多壁碳纳米管和纳米银线超声分散于溶剂中;最后,通过层层自组装制备纳米纤维素/碳纳米管/纳米银线复合电极,同时,作为对照组,制备纳米纤维素/碳纳米管复合电极。结果纳米纤维素纤丝的直径大约为30~100 nm,相互之间缠绕成网状结构,是很好的支撑材料,纳米纤维素/碳纳米管/纳米银线复合电极具有很好的成膜性和电化学性能,在扫描速率为30 m V/s时,面积比电容达到77.95 m F/cm^2。结论以纳米纤维素为基底,通过层层自组装方法制备的纳米纤维素/碳纳米管/纳米银线复合电极具有较好的电化学性能,可作为柔性超级电容器的电极。
