Non-volatile, Li-doped ion gel electrolytes for flexible WO₃-based electrochromic devices

Yun, Tae Yong,Li, Xinlin,Bae, Jaehyun,Kim, Se Hyun,Moon, Hong Chul Elsevier 2019 Materials & Design Vol.162 No.-

<P><B>Abstract</B></P> <P>Flexible electrochromic devices (ECDs) based on Li-doped ion gels and tungsten trioxide (WO<SUB>3</SUB>) are demonstrated. Colored ECDs cannot be produced using conventional ion gels comprised of copolymers and room temperature ionic liquids (RTILs) due to a lack of cations that can be inserted into WO<SUB>3</SUB>. Based on considerations of the coloration mechanism, we developed Li-doped ion gels and applied these to devices. The effects of Li salt concentration are systematically examined, with respect to device dynamics, coloration efficiency, and transmittance contrast. In addition, the coloration/bleaching switching stability of the ECD produced using optimal Li salt content is investigated. The ECD exhibits distinct colored and bleached states even after 24 h operation in air. Using the described Li-doped ion gel electrolytes, flexible WO<SUB>3</SUB> ECDs were successfully demonstrated with good bending stability and no electrolyte leakage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Non-volatile, Li-doped ion gel electrolytes are designed for flexible WO<SUB>3</SUB>-based ECDs. </LI> <LI> ECDs exhibit low voltage operation (–0.9 V) and large transmittance contrast (~85%) between colored and bleached states. </LI> <LI> Electrolyte leakage is not observed in flexible ECDs containing Li-doped gel electrolyte when bending deformation is applied. </LI> <LI> Flexible ECDs maintain ~90.3 and ~84.5% of initial optical transmittance and coloration efficiency after 1000 bending tests. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fabrication of Fast-response Ultraviolet Light Sensors with LZO Thin Films using Sol-gel Spin-coating Method

김동완,임재영 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.3

The Li-doped ZnO (LZO) thin films with various Li concentrations (0, 1, 3, 5, 7, and 9 at.%)were deposited on quartz substrates by sol-gel spin-coating method. The effects of Li doping onthe structural and optical properties of the thin films were investigated. Undoped ZnO thin filmand LZO thin films had three different diffraction peaks at 31.5 , 34.2 , and 36.0 corresponding tothe ZnO (100), (002), and (101) planes, respectively. The c-axis orientation of the LZO thin filmsincreased with increasing Li doping concentration, owing to the high diffusivity of the Li dopant. Abroad red emission was observed by photoluminescence of the undoped ZnO thin film, whereas LZOthin films had broad green emissions. The transmittance and optical band gap blue-shifted withincreasing Li doping concentration. In terms of photoresponse, all LZO thin films had greater riseand decay rates than the undoped ZnO thin film and the photosensitivity increased with increasingLi doping concentration.

Adipic Acid Assisted Sol-Gel Synthesis of Li_1+x(Mn_0.4Ni_0.4Fe_0.2)_1-xO₂ (0 < x < 0.3) as Cathode Materials for Lithium Ion Batteries

Karthikeyan, Kaliyappan,Amaresh, Samuthirapandian,Son, Ju-Nam,Kim, Shin-Ho,Kim, Min-Chul,Kim, Kwang-Jin,Lee, Sol-Nip,Lee, Yun-Sung Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Layered $Li_{1+x}(Mn_{0.4}Ni_{0.4}Fe_{0.2})_{1-x}O_2$ (0 < x < 0.3) solid solutions were synthesized using solgel method with adipic acid as chelating agent. Structural and electrochemical properties of the prepared powders were examined by means of X-ray diffraction, Scanning electron microscopy and galvanostatic charge/discharge cycling. All powders had a phase-pure layered structure with $R\bar{3}m$ space group. The morphological studies confirmed that the size of the particles increased at higher x content. The charge-discharge profiles of the solid solution against lithium using 1 M $LiPF_6$ in EC/DMC as electrolyte revealed that the discharge capacity increases with increasing lithium content at the 3a sites. Among the cells, $Li_{1.2}(Mn_{0.32}Ni_{0.32}Fe_{0.16})O_2$ (x = 0.2)/$Li^+$ exhibits a good electrochemical property with maximum initial capacity of 160 $mAhg^{-1}$ between 2-4.5 V at 0.1 $mAcm^{-2}$ current density and the capacity retention after 25 cycles was 92%. Whereas, the cell fabricated with x = 0.3 sample showed continuous capacity fading due to the formation of spinel like structure during the subsequent cycling. The preparation of solid solutions based on $LiNiO_2-LiFeO_2-Li_2MnO_3$ has improved the properties of its end members.

Adipic Acid Assisted Sol-Gel Synthesis of Li1+x(Mn0.4Ni0.4Fe0.2)1-xO2 (0 < x < 0.3) as Cathode Materials for Lithium Ion Batteries

Kaliyappan Karthikeyan,Samuthirapandian Amaresh,Ju-Nam Son,Shin-Ho Kim,Min-Chul Kim,김광진,이윤성,Sol-Nip Lee 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Layered Li1+x(Mn0.4Ni0.4Fe0.2)1-xO2 (0 < x < 0.3) solid solutions were synthesized using solgel method with adipic acid as chelating agent. Structural and electrochemical properties of the prepared powders were examined by means of X-ray diffraction, Scanning electron microscopy and galvanostatic charge/discharge cycling. All powders had a phase-pure layered structure with R3m space group. The morphological studies confirmed that the size of the particles increased at higher x content. The charge-discharge profiles of the solid solution against lithium using 1 M LiPF6 in EC/DMC as electrolyte revealed that the discharge capacity increases with increasing lithium content at the 3a sites. Among the cells, Li1.2(Mn0.32Ni0.32Fe0.16)O2 (x = 0.2)/ Li+ exhibits a good electrochemical property with maximum initial capacity of 160 mAhg−1 between 2-4.5 V at 0.1 mAcm−2 current density and the capacity retention after 25 cycles was 92%. Whereas, the cell fabricated with x = 0.3 sample showed continuous capacity fading due to the formation of spinel like structure during the subsequent cycling. The preparation of solid solutions based on LiNiO2-LiFeO2-Li2MnO3 has improved the properties of its end members.

Preparation and Characterization of Mn-doped Li0.06(Na0.5K0.5)0.94NbO3 Lead-free Piezoelectric Ceramics with Surface Sol-gel Coatings

Ae Ri Yoo,이성의,이희철 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.3

This study investigated the effects of Mn doping and sol-gel surface coating on the structural andthe electrical properties of lead-free Li0.06(K0.5Na0.5)0.94NbO3(LNKN) ceramics in disc form for useas eco-friendly piezoelectric devices. The 1-mol% Mn-doped LNKN ceramic showed a relatively highpiezoelectric constant owing to its high density in the case of its being annealed at a temperatureof 1010 C. A Mn-doped LNKN sol-gel solution with the same composition as that of the ceramicswas spin-coated and sintered on both sides of the ceramic surfaces to acquire improved electricalproperties. The sol-gel surface coating could play a decisive role in filling the pores, resulting in flatand stable interfaces between the electrodes and the piezoelectric elements. As a result, the highestpiezoelectric constant, d33, of 173 pC/N could be obtained for the Mn-doped LNKN ceramics with420-nm-thick sol-gel surface coatings.

Structural and Electrical Features of Solution-Processed Li-doped ZnO Thin Film Transistor Post-Treated by Ambient Conditions

Taesung Kang,Jayhyun Koo,Taeyoon Kim,Jinpyo Hong 한국진공학회 2012 한국진공학회 학술발표회초록집 Vol.2012 No.8

Novel chelating agent assisted dual doped spinel via sol-gel method for lithium rechargeable batteries

Thirunakaran, R.,Lew, G.H.,Yoon, W.S. Elsevier Sequoia 2016 Journal of Electroanalytical Chemistry Vol.767 No.-

<P>LiMn2O4 and LiCuxAlyMn2-x-yO4 (x = 0.50; y = 0.05-0.50) powders have been synthesized via sol-gel method for the first time using Margaric acid as chelating agent. The synthesized samples have been used to physical and electrochemical characterization such as thermo gravimetric analysis (TG/DTA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and electrochemical characterization viz., electrochemical galvanostatic cycling studies, electrochemical impedance spectroscopy (EIS) and differential capacity curves (dQJdE). XRD patterns of LiMn2O4 and LiCuxAlyMn2-x-yO4 confirm high degree of crystallinity with better phase purity of synthesized materials. FESEM images of parent LiMn2O4 depict the most of the particles that are in 0.5 mu m while LiCu0.5Al0.05Mn1.45O4 powders exhibiting ice-cube surface morphology with good agglomerated less particle size of 50 nm. TEM images of spinel LiMn2O4 and LiCu0.5Al0.05Mn1.45O4 corroborate that all the synthesized particles are nano-sized with uniform spherical and cloudy particle morphology. LiMn2O4 samples calcined at 850 degrees C deliver the high discharge capacity of 130 mA h g(-1) in the first cycle while LiCu0.5Al0.05Mn1.45O4 samples deliver 120 mA h g(-1) during the first cycle. Inter alia all the dopant compositions investigated, LiCu0.5Al0.05Mn1.45O4 delivers the stable cycling performance of 119 and 115 mA h g(-1) in the 5th and 10th cycle with low capacity fade of 0.1 and 0.1 mA h g(-1) cycle(-1) corresponding to columbic efficiency of 99 and 99%. (C) 2016 Published by Elsevier B.V.</P>