氧化锌/Lyocell复合纤维的制备及性能

为实现纳米氧化锌与Lyocell纤维素溶液的共混纺丝,以N-甲基吗啉-N-氧化物(NNMO)水溶液作为分散介质,制备了NMMO基高分散型纳米氧化锌分散液。在此基础上,进一步通过原液共混工艺及干湿法纺丝工艺制备了不同氧化锌含量的氧化锌/Lyocell复合纤维。采用旋转流变仪、纳米粒度仪、光学显微镜、扫描电镜、透射电镜、X射线衍射仪、热重分析仪和纤维强伸度仪分别研究了纳米氧化锌的添加对Lyocell纤维素溶液的流变性能及对复合纤维结构与性能的影响。结果表明,经研磨分散后纳米氧化锌颗粒表面的Zeta电位值由-19.1 mV提升至-42 mV,与Lyocell纤维素溶液相容性较好;纳米氧化锌的添加提高了Lyocell纤维的热稳定性,当纳米氧化锌的质量分数为1%时,氧化锌/Lyocell复合纤维的初始分解温度较普通Lyocell纤维提高了26℃,断裂强度及初始模量分别提高了8.6%和10.4%;该复合纤维对大肠杆菌、金黄色葡萄球菌和白色念珠菌的抗菌率均在99%以上,洗涤20次后抗菌率无变化,具备优异的抗菌性能。

Long cycle performance of NC@VN/MnO cathode for AZIBs based on Mn/V relay type collaboration

Aqueous zinc ion batteries(AZIBs) have received great attention because of their non-toxicity,high safety,low cost,high abundance,and high specific power.However,their specific capacity is still low compared with lithium ion battery,and current academic research interesting has been focused on developing new cathode materials with high specific capacity.In this study,a Mn/V hybrid polymer framework is designed by a simple self-polymerization scheme.During subsequent calcination,ultrafine VN quantum dots and MnO nanoparticles are generated in situ and stably encapsulated inside N-doped carbon(NC) shells to obtain a novel hybrid cathode NC@VN/MnO for AZIBs.According to the density functional theory(DFT) calculation,the hybrids of MnO and VN can generate both interfacial effects and built-in electric fields that significantly accelerate ion and electron transport by tuning the intrinsic electronic structure,thus enhancing electrochemical performance.A synergistic strategy of composition and structural design allows the rechargeable AZIBs to achieve low-cost and excellent long-cycle performance based on a relay type collaboration at different cycling stages.Consequently,the NC@VN/MnO cathode has output a capacity of 108.3 mA h g^(-1)after 12,000 cycles at 10 A g^(-1).These results clearly and fully demonstrate the advantages of the hybrid cathode NC@VN/MnO.

Dense ceramics with complex shape fabricated by 3D printing:A review

Three-dimensional(3D)printing technology is becoming a promising method for fabricating highly complex ceramics owing to the arbitrary design and the infinite combination of materials.Insufficient density is one of the main problems with 3D printed ceramics,but concentrated descriptions of making dense ceramics are scarce.This review specifically introduces the principles of the four 3D printing technologies and focuses on the parameters of each technology that affect the densification of 3D printed ceramics,such as the performance of raw materials and the interaction between energy and materials.The technical challenges and suggestions about how to achieve higher ceramic density are presented subsequently.The goal of the presented work is to comprehend the roles of critical parameters in the subsequent 3D printing process to prepare dense ceramics that can meet the practical applications.

Novel fast lithium-ion conductor LiTa_(2)PO_(8)enhances the performance of poly(ethylene oxide)-based polymer electrolytes in all-solid-state lithium metal batteries

At present,replacing the liquid electrolyte in a lithium metal battery with a solid electrolyte is considered to be one of the most powerful strategies to avoid potential safety hazards.Composite solid electrolytes(CPEs)have excellent ionic conductivity and flexibility owing to the combination of functional inorganic materials and polymer solid electrolytes(SPEs).Nevertheless,the ionic conductivity of CPEs is still lower than those of commercial liquid electrolytes,so the development of high-performance CPEs has important practical significance.Herein,a novel fast lithium-ion conductor material LiTa_(2)PO_(8) was first filled into poly(ethylene oxide)(PEO)-based SPE,and the optimal ionic conductivity was achieved by filling different concentrations(the ionic conductivity is 4.61×10^(-4)S/cm with a filling content of 15 wt%at 60℃).The enhancement in ionic conductivity is due to the improvement of PEO chain movement and the promotion of LiTFSI dissociation by LiTa_(2)PO_(8).In addition,LiTa_(2)PO_(8) also takes the key in enhancing the mechanical strength and thermal stability of CPEs.The assembled LiFePO_(4) solid-state lithium metal battery displays better rate performance(the specific capacities are as high as 157.3,152,142.6,105 and 53.1 mAh/g under0.1,0.2,0.5,1 and 2 C at 60℃,respectively)and higher cycle performance(the capacity retention rate is86.5%after 200 cycles at 0.5 C and 60℃).This research demonstrates the feasibility of LiTa_(2)PO_(8) as a filler to improve the performance of CPEs,which may provide a fresh platform for developing more advanced solid-state electrolytes.

Improving cycling stability of Bi-encapsulated carbon fibers for lithium/sodium-ion batteries by Fe_(2)O_(3) pinning

Bi draws increasing attention as anode materials for lithium-ion batteries and sodium-ion batteries due to its unique layered crystal structure,which is in favor of achieving fast ionic diffusion kinetics during cycling.However,the dramatic volume expansion upon lithiation/sodiation and an insufficient theoretical capacity of Bi greatly hinder its practical application.Herein,we report the Fe_(2 )O_(3) nanoparticle-pinning Bi-encapsulated carbon fiber composites through the electrospinning technique.The introduction of Fe_(2 )O_(3) nanoparticles can prevent the growth and aggregation of Bi nanoparticles during synthetic and cycling processes,re s pectively.Fe_(2)O_(3) with high specific capacity also contributes to the specific capacity of the composites.Consequently,the as-prepared Bi-Fe_(2)O_(3)/carbon fiber composite exhibits outstanding long-term stability,which delivers reversible capacities 504 and 175 mAh/g after1000 cycles at 1 A/g for lithium-ion and sodium-ion batteries,respectively.