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>

사계 김장생의 이기론과 심성론 소고

이학당 ( Li Xue-tang ),왕천천 ( Wang Qian-qian ) 우리한문학회 2017 漢文學報 Vol.37 No.-

사계 김장생은 조선 중기의 저명한 예학가이고 교육가이다. 그는 스승 율곡의 "기발리승설"과 "리통기국설" 리기론 사상을 계승하면서 리와 기를 혼연일체의 존재로 보았다. 또한 리는 무형무위이고 기는 유형유위라고 보았다. 사계는 퇴계의 이기호발설을 부정한다. 그는 정호의 “기가 도이고 도가 기이다’는 주장을 근거로 이기불상리를 해석한다. 또한 주희의 “리는 리이고 기는 기이다”는 주장을 근거로 이기불상잡을 해석한다. 율곡이 제창한 ‘기발 이승’을 따르면서 리와 기는 “하나이면서 둘이고 둘이면서 하나다.”는 주장을 하면서 리와 기의 조화를 강조한다. 사계는 리와 기가 둘이면서 하나인 관계를 해석할 적에 이기가 합쳐지는 것이 시간적 선후로 구분하는 것은 아니라는 점을 밝힘과 동시에 공간적으로는 기가 리를 포함한다는 입장을 견지한다. 사계는 리는 기 안에 있고 원래 떨어지지 않는다고 하는데 이런 말은 기의 능동성을 중시하는 사계의 입장을 잘 보여주며 그의 심성론과 예악사상의 이론적 기초를 구성한다. 구용에 이해 방식은 사계 사상의 독자성을 보여준다. 사계는 송강이 “구용은 리이다”라고 하는 주장을 두고 체용을 원용하여 구용을 리의 작용으로 설명한다. 따라서 사계는 율곡의 입장에 기반하여 송강의 주장을 반대하지 않는다. 그러나 “형이상자는 기이고 형이하자는 도이다”는 구절에 대한 사계의 해석은 다소 문제가 있다. 사계는 도와 형을 다른 개념으로 이해하고 형과 기를 같은 개념으로 이해하는데 이런 이해는 사실에 부합하지 않는다. 사계는 율곡사상에 기초하여 심, 성, 정, 의, 지 등 성리학 심성론의 기초 개념을 심도 있게 해석한다. 본 연구는 이후 그가 주장하는 사단칠정론과 인심도심설의 이론적 토대가 된다. Shagai Kim jang-saeng was a famous scientist and educator in the middle of the Chosun Dynasty, on Confucianism he basicly inherited Zhu xi and Lee er's overall spirits, in the view of qi he claimedLi is of intangible and inaction, while Qi is of visible and action, so he denied Lee huang’s theory of which Li and Qi are inspired with each other. He cited Cheng hao’s theory of that "Qi is Dao and Dao is Qi" to explain the Li and Qi are not separated, and also quoted zhu xi's theory of that "Li is Li, Qi is Qi" to explain that the Li and Qi are not mixed. He agreed the Lee er’s idea of that"the Qi emits and Li follows " , he advocated "one is two, two is one", emphasizing the harmony of the Li and Qi. In the explanation of the relationship between "two is one", he was not only explained the combination of Li and Qi in chronological order, but also considered that the combination of Li and Qi was "Li was surrounded by Li"in space order. Shagai often said that "Li is in the Qi and they are not dissimilar"which reflected that he emphasised motility of the Qi, and also laid a theoretical foundation for his theory of mindand ritual thought. The understanding of the problem of "nine looks" reflected the autonomy of Shaxi’s thought. He believed that Songgang’s theory of which"nine looks are Li" was the use of Li from the perspective of body and function, so he did not denid Songgang's viewpoint in accordance with Lee er's thought. But he had some problems in the understanding of that "the person who is above, what is the Dao; There are some problems with the understanding of the "Meta physics is the Dao while the opposite is Qi". He seed that the Xing and Dao are different concept, but he thought that Xing and Qi are the same concept, which was lack of science. In terms of theory of mind, he based on the Yulgok’s thoughts, he made the detailed explanation for the basic concepts of neo-confucianism, such as the heart, character, feeling, idea, aspiration, whichbecame the necessary theoretical matting of the theory of four sides and seven feelings and the theory of people’s mind and Dao’s mind for the next step.

First-principles studies of K₁ ₋ _xM_xMgH₃ (M = Li, Na, Rb, or Cs) perovskite hydrides for hydrogen storage

Li, Yuanyuan,Mi, Yiming,Chung, Jin Suk,Kang, Sung Gu Elsevier 2018 International journal of hydrogen energy Vol.43 No.4

<P><B>Abstract</B></P> <P>The structural stability and hydrogen release properties of M-doped KMgH<SUB>3</SUB> (M = Li, Na, Rb, or Cs) were examined using density functional theory (DFT) calculations. The reaction enthalpies (ΔH) of the four possible dehydrogenation reaction pathways were calculated using the doped structures with different phases ( P m 3 ¯ m , P<I>nma</I>, and R3<I>c</I>). The most favorable reaction pathway among these four pathways was found. Among the dopants investigated, the most promising dopant for this reaction was Li. In addition, the application of pressure was found to be useful for tuning the reaction enthalpies of the dehydrogenation reactions. Overall, the results present an efficient means of designing new promising perovskite-type hydrides for hydrogen storage.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Perovskite-type KMgH<SUB>3</SUB> is a promising candidate for hydrogen storage. </LI> <LI> The most favorable reaction pathway of dehydrogenation reactions was examined. </LI> <LI> Li was the most useful and effective dopant to release hydrogen. </LI> <LI> Pressure can be usefully employed for tuning the reaction enthalpies of dehydrogenation reactions. </LI> </UL> </P>

Effect of Zn2+ and F- Co-Modification on the Structure and Electrochemical Performance of Li4Ti5O12 Anode Material

Aijia Wei,Wen Li,Lihui Zhang,Xiaohui Li,Xue Bai,Zhenfa Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.5

Zn2+ and F- ions are successfully used to modify pure Li4Ti5O12 via a co-precipitation method followed by calcination at 400℃ for 5 h in an Ar atmosphere in order to further investigate the reaction mechanism of the fluoride modification process. Zn2+ and F- co-modified Li4Ti5O12 samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. After the modification process, no ZnF2 coating layer is formed on the surface of Li4Ti5O12, instead, F- ions react with Li4Ti5O12 to generate a new phase, composed of a small amount of anatase TiO2, rutile TiO2, LiF, and Zn2+ ions are suspected to form a ZnO coating layer on Li4Ti5O12 particles. The electrolyte reduction decomposition is suppressed in Zn2+ and F- co-modified Li4Ti5O12 due to the ZnO coating layer. 1 wt.% Zn2+ and F- co-modified Li4Ti5O12 exhibits the best rate capability, which leads to a charge capacity of 236.7, 227.8, 222.1, 202.7, 188.9 and 150.7 mAh g -1 at 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively, between 0 V and 3 V. Furthermore, 1 wt.% Zn2+ and F- comodified Li4Ti5O12 exhibits 96.0% charge capacity retention at 3C rate after 200 cycles, which is significantly higher than that of pure Li4Ti5O12 (78.4%).

First-principles calculations of the effect of Ge content on the electronic, mechanical and acoustic properties of Li17Si4-xGex

Xiaohong Li,Hong-Ling Cui,Rui-Zhou Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.6

The electronic, mechanical and acoustic properties of Li17Si4-xGex (x=0, 2.3, 3.08, 3.53, and 4) have been investigated by using first-principles calculations based on the density functional theory (DFT). The research shows that the bulk modulus B, Young's modulus E, shear modulus G, and hardness Hv gradually decrease with the increasing Ge content. Li17Si4-xGex have the brittle nature from the analysis of B/G ratio and Cauchy pressure. The maximum Young's moduli are all along [1 1 0] plane, and the sequence of degree of anisotropic property is Li17Ge4 > Li17Si0.48Ge3.52 > Li17Si0.92Ge3.08 > Li17Si1.7Ge2.3 > Li17Si4. The analysis of acoustic velocity shows that all the sound velocities decrease with the increasing Ge content for Li17Si4-xGex (x=0, 2.3, 3.08, 3.53, and 4), and the longitudinal wave along [111] direction is fastest for the studied compounds. Debye temperature ΘD, vt and vl decrease with the increasing Ge content. The minimum thermal conductivity decreases with the increasing Ge content, and Li17Si4-xGex have low thermal conductivities and are not potential thermal conductors. The analysis of electronic properties indicates that Li17Si4-xGex have the metal nature and anisotropic electrical conductivity. The electric conduction is improved with the increasing Ge content.

A polymeric composite protective layer for stable Li metal anodes

Guo Suogang,Wang Li,Jin Yuhong,Piao Nan,Chen Zonghai,Tian Guangyu,Li Jiangang,Zhao Chenchen,He Xiangming 나노기술연구협의회 2020 Nano Convergence Vol.7 No.21

Lithium (Li) metal is a promising anode for high-performance secondary lithium batteries with high energy density due to its highest theoretical specific capacity and lowest electrochemical potential among anode materials. However, the dendritic growth and detrimental reactions with electrolyte during Li plating raise safety concerns and lead to premature failure. Herein, we report that a homogeneous nanocomposite protective layer, prepared by uniformly dispersing ­AlPO 4 nanoparticles into the vinylidene fluoride-co-hexafluoropropylene matrix, can effectively prevent dendrite growth and lead to superior cycling performance due to synergistic influence of homogeneous Li plating and electronic insulation of polymeric layer. The results reveal that the protected Li anode is able to sustain repeated Li plating/stripping for > 750 cycles under a high current density of 3 mA cm −2 and a renders a practical specific capacity of 2 mAh cm −2 . Moreover, full-cell Li-ion battery is constructed by using ­LiFePO 4 and protected Li as a cathode and anode, respectively, rendering a stable capacity after 400 charge/discharge cycles. The current work presents a promising approach to stabilize Li metal anodes for next-generation Li secondary batteries.

In-situ PECVD-enabled graphene-V₂O₃ hybrid host for lithium–sulfur batteries

Song, Yingze,Zhao, Wen,Wei, Nan,Zhang, Li,Ding, Feng,Liu, Zhongfan,Sun, Jingyu Elsevier 2018 Nano energy Vol.53 No.-

<P><B>Abstract</B></P> <P>Lithium–sulfur (Li–S) batteries have been regarded as promising candidates for current energy-storage technologies due to their remarkable advantages in energy density and theoretical capacity. However, one of the daunting challenges remained for advanced Li–S systems thus far deals with the synchronous suppression of polysulfide (LiPS) shuttle and acceleration of redox kinetics. Herein, a cooperative interface bridging adsorptive V<SUB>2</SUB>O<SUB>3</SUB> and conductive graphene is constructed <I>in-situ</I> by virtue of direct plasma-enhanced chemical vapor deposition (PECVD), resulting in the design of a novel V<SUB>2</SUB>O<SUB>3</SUB>-graphene hybrid host to synergize the LiPS entrapment and conversion. The redox kinetics and electrochemical performances of thus-derived cathodes were accordingly enhanced owing to the smooth adsorption-diffusion-conversion of LiPSs even at a sulfur mass loading of 3.7 mg cm<SUP>–2</SUP>. Such interfacial engineering offers us a valuable opportunity to gain insight into the comprehensive regulation of LiPS anchoring ability, electrical conductivity and ion diffusive capability in hybrid hosts on suppressing the LiPS shuttle and propelling the redox kinetics. Our devised PECVD route might pave a new route toward the facial and economic design of hetero-phased multi-functional hosts for high-performance Li–S systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Graphene-V<SUB>2</SUB>O<SUB>3</SUB> hybrid host was designed <I>in-situ</I> based on PECVD route. </LI> <LI> Thus-derived cathode showed a low capacity decay of merely 0.046% per cycle at 2 C after 1000 cycles. </LI> <LI> Cathodes with a relatively high sulfur mass loading (3.7 mg cm<SUP>–2</SUP>) were fabricated. </LI> <LI> The smooth adsorption-diffusion-conversion of polysulfides was thoroughly probed <I>via</I> experimental studies and DFT simulations. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

White-Matter Hyperintensities and Lacunar Infarcts Are Associated with an Increased Risk of Alzheimer’s Disease in the Elderly in China

Shuai Ye,Shuyang Dong,Jun Tan,Le Chen,Hai Yang,Yang Chen,Zeyan Peng,Yingchao Huo,Juan Liu,Mingshan Tang,Yafei Li,Huadong Zhou,Yong Tao 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.1

Background and Purpose This study investigated the contribution of white-matter hyperintensities (WMH) and lacunar infarcts (LI) to the risk of Alzheimer’s disease (AD) in an elderly cohort in China. Methods Older adults who were initially cognitively normal were examined with MRI at baseline, and followed for 5 years. WMH were classified as mild, moderate, or severe, and LI were classified into a few LI (1 to 3) or many LI (≥4). Cognitive function was assessed using the Mini Mental State Examination and the Activities of Daily Living scale. Results Among the 2,626 subjects, 357 developed AD by the end of the 5-year follow-up period. After adjusting for age and other potential confounders, having only WMH, having only LI, and having both WMH and LI were associated with an increased risk of developing AD compared with having neither WMH nor LI. Moderate and severe WMH were associated with an increased risk of developing AD compared with no WMH. Furthermore, patients with many LI had an increased risk of developing AD compared with no LI. Conclusions Having moderate or severe WMH and many LI were associated with an increased risk of developing AD, with this being particularly striking when both WMH and LI were present.

Recent Developments in the Effects of Different Dopants on the Structure and Property of Lithium Titanate Material

Xi-Yang Li,Qian-Lin Chen,Min Yang,Ya-Nan Li,Jing-Bo Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

The lithium titanium spinel Li4Ti5O12 has attracted more and more attention as anode materials applied in lithium ion batteries. Li4Ti5O12 material has been found to be able to intercalate lithium ions without deformation of the lattice. However, compared with graphite and other anode materials, the low conductivity of Li4Ti5O12 restricts its charging and discharging rate. Doping is deemed to be a businesslike method to enhance ionic and electronic conductivity of Li4Ti5O12. This paper reviews the effects of Li4Ti5O12 with different doping ions on different crystal lattice states. And it has been found by a summary that the doping objective of doping ions at Li4Ti5O12 is also different. Moreover, the applications of ion doping in different fields of Li4Ti5O12 are prospected.

Designed seamless outer surface: Application for high voltage LiNi_0.5Mn_1.5O₄ cathode with excellent cycling stability

Zhang, Kan,Li, Ping,Ma, Ming,Park, Jong Hyeok Elsevier 2016 Journal of Power Sources Vol.336 No.-

<P><B>Abstract</B></P> <P>Suppressing side reactions at the cathode-electrolyte interface (CEI) is critical for alleviating capacity fading of the high-voltage (>5 V) spinel cathode material LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB> (LNMO). The primary bottleneck in conventional nanoengineering of LNMO involves an antagonistic relationship between the positive effects of the nanometer particle size and negative effects stemming from the larger CEI area. Inspired by Buckminster Fuller's geodesic domes, we have designed a seamless LNMO hollow sphere (S-LNMO) that comprises average 120 nm-sized triangles and truncated triangle subunits by means of grain growth orientation. The “tensegrity” structure has efficiently hindered the interfacial side reaction, which occurs only within a depth of 5 nm from the surface, thereby improving its electrochemical stability. The embedded layered Li<SUB>2</SUB>TiO<SUB>3</SUB> (LTO) in bulk S-LNMO (LTO:S-LNMO) region further improved the high-rate performance, demonstrating an ∼110 mAh/g capacity with 80.9% retention after 400 cycles at 5 C and remaining stable after 900 cycles at 5 C even after being stored at 50 °C for one week.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Seamless disordered Fd3m-phase LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB> hollow spheres are subtly designed. </LI> <LI> The seamless architecture minimized the interfacial side reaction. </LI> <LI> Nanometer depth analysis showed an electrolyte permeation distance of less than 5 nm. </LI> <LI> A layered Li<SUB>2</SUB>TiO<SUB>3</SUB> embedded in LiNi<SUB>0.5</SUB>Mn<SUB>1.5</SUB>O<SUB>4</SUB> enables high-rate performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>