Superhydrophobic ceramic hollow fiber membrane planted by ZnO nanorod-array for high-salinity water desalination

Wang, Tao,Yun, Yanbin,Wang, Manxiang,Li, Chunli,Liu, Guicheng,Yang, Woochul Elsevier 2019 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.105 No.-

<P><B>Abstract</B></P> <P>To solve the problems of membrane material tolerance and membrane fouling, a micro/nano hierarchial structure with low surface energy was constructed above the exterior surface of a ceramic hollow fiber membrane using ZnO nanorod arrays and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDTS) coatings, which make it superhydrophobic and self-cleaning. The surface morphology, chemical functional groups, and water contact angel of the modified membranes were identified. The results show that large quantity of ZnO nanorods possess desirable characteristics (<I>i.e.</I> superhydrophobicity, exceptional thermal and mechanical stability, and water contact angle of 160.12°) were detected on the ceramic membrane. The novel membrane shows excellent self-cleaning performance and good desalination ability in the utilization of vacuum membrane distillation (VMD) system for high-salinity water desalination.</P> <P><B>Highlights</B></P> <P> <UL> <LI> • Ceramic membrane is modified by imitating of superhydrophobic biological surfaces. </LI> <LI> • The micro/nano hierarchical structure with low surface energy endows the superhydrophobicity. </LI> <LI> • The P-ZN-CHF membrane obtains antifouling ability. </LI> <LI> • The modified membrane shows excellent performances during vacuum membrane distillation. </LI> </UL> </P>

ZnO Nanorod Array Modified PVDF Membrane with Superhydrophobic Surface for Vacuum Membrane Distillation Application

Wang, Manxiang,Liu, Guicheng,Yu, Hyunjin,Lee, Sang-Hyup,Wang, Lei,Zheng, Jianzhong,Wang, Tao,Yun, Yanbin,Lee, Joong Kee American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.16

<P>The vacuum membrane distillation (VMD) is a promising technology for lots of applications. To solve the membrane fouling and wetting problems, in this paper, a novel ZnO nanorods 1<I>H</I>,1<I>H</I>,2<I>H</I>,2<I>H</I>-perfluorodecyltriethoxysilane (PDTS) modified poly(vinylidene fluoride) (PVDF) membrane with a micro/nanoscale hierarchical structure and a superhydrophobic surface has been prepared and applied to the VMD process for distilling highly salty water, for the first time. Among these, a pyrolysis-adhesion method is created to obtain the ZnO seeds and fasten them on the PVDF substrate firmly. The novel modified membrane shows a stable superhydrophobic surface with a water contact angle of 152°, easy cleaning property, excellent thermal and mechanical stability, because of the Cassie’s state caused by pocketing much air in the hydrophobized ZnO nanorods, the low surface energy of PDTS coating, and the strong adhesion between ZnO nanorods and PVDF membrane, which has built an ideal structure for VMD application. After 8 h VMD of 200 g L<SUP>-1</SUP> NaCl solution, compared to the virgin PVDF membrane, the novel membrane shows a similar permeate flux but a much higher quality permeated liquid because of its unique antifouling and antiwetting caused by the several microns gap between the feed and the membrane. Due to its easy cleaning property, the novel membrane also exhibits an excellent reusability.</P> [FIG OMISSION]</BR>

Microstructure-modified proton exchange membranes for high-performance direct methanol fuel cells

Wang, Manxiang,Liu, Guicheng,Tian, Zhe,Shao, Yingna,Wang, Lei,Ye, Feng,Tran, Minh Xuan,Yun, Yanbin,Lee, Joong Kee Elsevier 2017 Energy conversion and management Vol.148 No.-

<P><B>Abstract</B></P> <P>To lower methanol crossover and volume swelling degree, and to improve proton conductivity, a simple hot-mould-modifying method has been introduced to modify Nafion membrane for the direct methanol fuel cell application. To evaluate effect of the modification on properties of the Nafion membrane and fuel cell performance, a series of measurements of membranes and fuel cells have been carried out. The results show that, compared with the normal membrane, the modified Nafion membrane with regular spindle-type groove array possesses higher proton conductivity and methanol diffusion resistance, and 31.9% better dimensional stability, owing to its larger electrical double-layer capacitance come from the higher contact area between electron-electrode and ion electrolyte, and its more compact internal structure. And also, the direct methanol fuel cell based on the modified Nafion membrane shows 13.3% higher discharge power density and better long-time running performance than the normal one. Furthermore, this hot-mould-modifying method could be introduced into doping/coating-modified membranes reported in the current literature to further modify Nafion membranes, because this method is compatible with the current modifications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simple hot-mould-modified Nafion membrane is used for direct methanol fuel cells. </LI> <LI> Regular spindle-type groove array is uniformly distributed on the membrane surface. </LI> <LI> Modification lowers methanol crossover, swelling, and improves proton conductivity. </LI> <LI> Power density and long-time running performance of fuel cells are improved visibly. </LI> <LI> This method provides a practicable way for direct methanol fuel cell applications. </LI> </UL> </P>

A novel flexible micro-ratchet/ZnO nano-rods surface with rapid recovery icephobic performance

Wang, Manxiang,Yu, Wenbo,Zhang, Yupei,Woo, Jae-Young,Chen, Yu,Wang, Bo,Yun, Yanbin,Liu, Guicheng,Lee, Joong Kee,Wang, Lei Elsevier 2018 Journal of industrial and engineering chemistry Vol.62 No.-

<P><B>Abstract</B></P> <P>In this communication, we present a significant method to fabricate a robust icephobic surface on a flexible polymer substrate. The flexible functional surface is obtained by integrating both soft-lithography and crystal growth methods. Modified by the materials with low surface free energy, the composite surface exhibits a robust superhydrophobicity at not only room temperature but also low temperature. After freezing test, the surface can recover to its original function quickly, which has achieved the level for industrial application, and also performed significant role for enhancing the icephobic theories.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO nano-rods are uniformly planted on the flexible PDMS surface. </LI> <LI> Fabrication of the surface integrates both crystal growth and physical vapor deposition methods. </LI> <LI> The superhydrophobic surface successfully realizes fast-recovery from freezing state. </LI> <LI> In freezing process, the nanorods can hardly cracked due to the flexible basement. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The liquid droplet can recover to sphere state (Cassie's state) after melting from low temperature (for example, 20°C). ▪</P> <P>[DISPLAY OMISSION]</P>

Controversy on necessity of cobalt in nickel-rich cathode materials for lithium-ion batteries

Rui Wang,Lifan Wang,Yujie Fan,Woochul Yang,Chun Zhan,Liu Guicheng 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

Since the layered oxide LiCoO2 as the cathode material for commercial Li ion batteries, especially, nickelrichlayered oxide cathode materials are consolidating their status as the cathode material of choice andenabling a significant success of the passenger electric vehicle industry. Generally, cobalt in cathodes hasbeen considered necessary in enhancing electrochemical performance. However, they are still facing criticalchallenges in further commercialization. For instance, cobalt caused more severe structural degradationand capacity degradation at high potential. Additionally, it triggered O2 and heat release, whicheventually cause the interfacial instability and thermal instability of the cathode materials. Prior studiesalso confirmed that cobalt plays double-edged roles in cathodes, and questioned its necessity. Meanwhile, not only is it facing a roadblock caused by high-cost restrictions, but more importantly,50% of world mine production originates from copper-cobalt ore in the Democratic Republic of theCongo (DRC), where geopolitical instability and harsh working conditions could halt cobalt exports. Therefore, many studies have explored the possibility of cobalt-free materials. This review shed newlights on understanding the role of cobalt and reveals the perspectives of technical challenges in currentstate by the practical aspect for cobalt-free cathode materials, thereby helping to advance the futuredevelopment of next-generation low-cost and long-calendar-life batteries.

Robust anti-icing performance of silicon wafer with hollow micro-/nano-structured ZnO

Lei Wang,Chao Teng,Jing Liu,왕만상,Liu Guicheng,김지영,Qiwen Mei,이중기,Jingxia Wang 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.62 No.-

A novel silicon-based robust anti-icing surface with hollow micro-/nano-structured ZnO (HMN) is investigated. The droplet could not freeze in 30 min under low temperature of −15 °C, while that performance fails on the nano-structured and smooth surfaces. The cooling period of temperature fields on liquid droplet and the base are observed, which indicates that the air layer has a significant effect on the performance of the anti-icing surface. The results prove that the hollow micro-structure layer provides much more air than the nano-structured layer and induces the maximum thermal resistance, leading to its icephobic property. In this finding, HMN provides large thermal resistance between the base and liquid droplet and easily realizes long lasting anti-icing performance under lower temperature. This new concept is expected to be used in the fields of anti-icing, superhydrophobicity, insulation, thermal resistance, etc.

Study on a stretchable, fiber-shaped, and TiO₂ nanowire array-based dye-sensitized solar cell with electrochemical impedance spectroscopy method

Liu, Guicheng,Wang, Hui,Wang, Manxiang,Liu, Wenbing,Anugrah Ardhi, Ryanda Enggar,Zou, Dechun,Lee, Joong Kee Elsevier 2018 ELECTROCHIMICA ACTA Vol.267 No.-

<P><B>Abstract</B></P> <P>A spring-like Ti@TiO<SUB>2</SUB> nanowire array wire has been introduced into a stretchable fiber-shaped dye-sensitized solar cell (FDSSC) as a photoanode to achieve high flexibility and elasticity in this paper. Given the TiO<SUB>2</SUB> layer, which was prepared by a hydrothermal reaction in the optimized NaOH concentration of 2.5 mol L<SUP>−1</SUP>, with a 1D structure and high adhesion between the TiO<SUB>2</SUB> nanowire array and the Ti wire substrate, the novel FDSSC still possesses photoelectric conversion efficiency retention rates of approximately 97.00% and 95.95% after bending to a radius of 1.0 cm and stretching to 100% strain, respectively. EIS result shows the degradation mechanism of the FDSSC photoelectric performance: the bending test leads to more terrible electron combination; the stretching operation increases the internal resistance and charge-transfer resistance at the counter electrode. Moreover, it's worth noting that, this is the first time to show a 100%-stretching degree in the FDSSC research field so far.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A fiber-shaped, stretchable, TiO<SUB>2</SUB> nanowire array-based DSSC was reported firstly. </LI> <LI> Using EIS analysis method to analyse effect of bending and stretching on FDSSC performance. </LI> <LI> Photoelectric conversion efficiency retention rate of 95.95% after stretching to 100% strain. </LI> <LI> High flexibility with 97.00% performance retention rate at bending radius of 1 cm. </LI> </UL> </P>

Soft, Highly Elastic, and Discharge-Current-Controllable Eutectic Gallium-Indium Liquid Metal-Air Battery Operated at Room Temperature

Liu, Guicheng,Kim, Ji Young,Wang, Manxiang,Woo, Jae-Young,Wang, Lei,Zou, Dechun,Lee, Joong Kee Wiley (John WileySons) 2018 Advanced energy materials Vol.8 No.16

Hierarchically structured photoanode with enhanced charge collection and light harvesting abilities for fiber-shaped dye-sensitized solar cells

Liu, Guicheng,Wang, Manxiang,Wang, Hui,Ardhi, Ryanda Enggar Anugrah,Yu, Hyunjin,Zou, Dechun,Lee, Joong Kee Elsevier 2018 Nano energy Vol.49 No.-

<P><B>Abstract</B></P> <P>The performances of fiber dye-sensitized solar cells (FDSSCs), in terms of charge collection efficiency, light-harvesting ability, and structural stability, are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire substrate. The microridge made of several Ti micropits is inserted into TiO<SUB>2</SUB> layer to shorten the photoelectron transport distance from the original place in the TiO<SUB>2</SUB> layer to substrate and to increase the electron transport rate. The Ti micropits are used as light-gathering centers to collect the reflected light. Meanwhile, the Ti nanorods are evenly distributed on the surface of the microridge-coated Ti wire substrate, which increases the contact area between the substrate and the TiO<SUB>2</SUB> layer in order to suppress the electron recombination and scatters the incident light to further improve the light-harvesting ability. Therefore, the charge collection and power conversion efficiencies of the novel FDSSC have been accordingly enhanced by 17.7% and 61.6%, respectively, compared with traditional FDSSC. Moreover, the structural stability of the novel FDSSC has been strengthened.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchically structured photoanode substrate is a Ti microridge/nanorod-modified wire. </LI> <LI> Novel design enhances charge collection and light-harvesting abilities, concurrently. </LI> <LI> Novel FDSSC exhibits the highest PCE of 8.128% in the field of nanocrystalline-based FDSSCs so far. </LI> <LI> Ti microridges shorten photoelectron transport distance and are used as light-gathering centers. </LI> <LI> Ti nanorods suppress electron recombination and scatters the incident light. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The performances such as charge collection efficiency, light-harvesting ability and structural stability of fiber dye-sensitized solar cells (FDSSCs) are improved through a novel hierarchically structured photoanode based on a Ti microridge/nanorod-modified wire-substrate.</P> <P>[DISPLAY OMISSION]</P>

Design of 3-electrode system for <i>in situ</i> monitoring direct methanol fuel cells during long-time running test at high temperature

Liu, Guicheng,Li, Xinyang,Wang, Hui,Liu, Xiuying,Chen, Ming,Woo, Jae Young,Kim, Ji Young,Wang, Xindong,Lee, Joong Kee Elsevier 2017 APPLIED ENERGY Vol.197 No.-

<P>To understand the effect mechanisms of long-time running and high operation temperature on performance of the direct methanol fuel cell (DMFC) more clearly and directly, in this paper, a new design of 3-electrode system with a solution-type salt bridge has been developed to distinguish the integral polarization into anodic and cathodic polarizations at various temperatures and explore the attenuation mechanism by in situ monitoring the potential of anode during long-time running process at 80 degrees C, for the first time. The results indicate that the optimized 3-electrode system consists of a standard calomel electrode (SCE) and a solution-type salt bridge placed in the anode hole filled by 0.5 mol L-1 H2SO4 solution. By utilization of the 3-electrode system, the effect mechanisms of the running temperature and time on electrochemical parameters of the DMFC have been found: (1) The increasing operation temperature improves cathodic performance more significantly than that of anode; (2) the attenuation of fuel cell performance mainly comes from that of anode during the 20-h running test at 80 degrees C, resulting from the sharp drop of electrochemical active surface area of anode. More important, the new 3-electrode system has simplified the detection equipment and reduced the operating difficulty in a practical application for DMFCs, resulting in its portability. (C) 2017 Elsevier Ltd. All rights reserved.</P>