In zinc-air batteries, the gel polymer electrolyte (GPE) is an important factor for improving performance. The rigid physical properties of polyvinyl alcohol reduce ionic conductivity, which degrades the performance of the batteries. Zinc acetate is an effective additive that can increase ionic conductivity by weakening the bonding structure of polyvinyl alcohol. In this study, polymer electrolytes were prepared by mixing polyvinyl alcohol and zinc acetate dihydride. The material properties of the prepared polymer electrolytes were analyzed by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Also, Electrochemical impedance spectroscopy was used to calculate ionic conductivity. The electrolyte resistances of GPE, 0.2 GPE, 0.4 GPE, and 0.6 GPE were 0.394, 0.338, 0.290, and 0.213 Ω, respectively. In addition, 0.6 GPE delivered 0.023 S/cm high ionic conductivity. Among all of the polymer electrolytes tested, 0.6 GPE showed enhanced cycle life performance and the highest specific discharge capacity of 11.73 mAh/cm2 at 10 mA. These results verified that 0.6 GPE improves the performance of zinc-air batteries.

Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N2 reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g-1 at a current density of 100 mA g-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.

There is ongoing research to develop lithium ion batteries as sustainable energy sources. Because of safety problems, solid state batteries, where electrolytes are replaced with solids, are attracting attention. Sulfide electrolytes, with a high ion conductivity of 103 S/cm or more, have the highest potential performance, but the price of the main materials is high. This study investigated lithium hydride materials, which offer economic advantages and low density. To analyze the change in ion conductivity in polymer electrolyte composites, PVDF, a representative polymer substance was used at a certain mass ratio. XRD, SEM, and BET were performed for metallurgical analyses of the materials, and ion conductivity was calculated through the EIS method. In addition, thermal conductivity was measured to analyze thermal stability, which is a major parameter of lithium ion batteries. As a result, the ion conductivity of LiH was found to be 106 S/cm, and the ion conductivity further decreased as the PVDF ratio increased when the composite was formed.

Tin/graphite composites are prepared as anode materials for Li-ion batteries using a dry ball-milling process. The main experimental variables in this work are the ball milling time (0–8 h) and composition ratio (tin:graphite=5:95, 15:85, and 30:70 w/w) of graphite and tin powder. For comparison, a tin/graphite composite is prepared using wet ball milling. The morphology and structure of the different tin/graphite composites are investigated using X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, and scanning and transmission electron microscopy. The electrochemical properties of the samples are also examined. The optimal dry ball milling time for the uniform mixing of graphite and tin is 6 h in a graphite-30wt.%Sn sample. The electrode prepared from the composite that is dry-ballmilled for 6 h exhibits the best cycle performance (discharge capacity after 50th cycle: 308 mAh/g and capacity retention: 46%). The discharge capacity after the 50th cycle is approximately 112 mAh/g, higher than that when the electrode is composed of only graphite (196 mAh/g after 50th cycle). This result indicates that it is possible to manufacture a tin/graphite composite anode material that can effectively buffer the volume change that occurs during cycling, even using a simple dry ball-milling process.

As the size of market for electric vehicles and energy storage systems grows, the demand for lithium-ion batteries (LIBs) is increasing. Currently, commercial LIBs are fabricated with liquid electrolytes, which have some safety issues such as low chemical stability, which can cause ignition of fire. As a substitute for liquid electrolytes, solid electrolytes are now being extensively studied. However, solid electrolytes have disadvantages of low ionic conductivity and high resistance at interface between electrode and electrolyte. In this study, Li7La3Zr2O12 (LLZO), one of the best ion conducting materials among oxide based solid electrolytes, is fabricated through RF-sputtering and various electrochemical properties are analyzed. Moreover, the electrochemical properties of LLZO are found to significantly improve with co-sputtered Li2O. An all-solid thin film battery is fabricated by introducing a thin film solid electrolyte and an Li4Ti5O12 (LTO) cathode; resulting electrochemical properties are also analyzed. The LLZO/Li2O (60W) sample shows a very good performance in ionic conductivity of 7.3  108 S/cm, with improvement in c-rate and stable cycle performance.

The carbon spheres (CSs) synthesized by an ultrasonic-spray pyrolysis method were activated for supercapacitor electrode. There are plenty of cracks on the surface of the activated carbon spheres (ACSs), which expend with increasing the activation temperature and activator dosage. The specific capacitance of ACSs increases with the activation temperature and activator dosage and reach to maximal value at certain conditions. Importantly, the ACS sample activated at relatively low activation temperature (600 °C) and 7 of mass ratio of KOH to CSs has the highest specific capacitance (about 209 F g− 1 at 50 mA g− 1 of current density) and indicates the excellent cycling stability after 1000 consecutive charge–discharge cycles. Furthermore, the graphene sheets could be found in the samples that were activated at 1000 °C. And the electrode prepared by the sample has the very low series resistance because of the excellent conductivity of the formed graphene sheets.

A zinc-air battery consists of a zinc anode, an air cathode, an electrolyte, and a separator. The active material of the positive electrode is oxygen contained in the ambient air. Therefore, zinc-air batteries have an open cell configuration. The external condition is one of the main factors for zinc-air batteries. One of the most important external conditions is temperature. To confirm the effect of temperature on the electrochemical properties of zinc-air batteries, we perform various analyses under different temperatures. Under 60 oC condition, the zinc-air cell shows an 84.98 % self-discharge rate. In addition, high corrosion rate and electrolyte evaporation rate are achieved at 60 oC. Among the cells stored at various temperature conditions, the cell stored at 50 oC delivers the highest discharge capacity; it also shows the highest self-discharge rate (65.33 %). On the other hand, the cell stored at 30 oC shows only 2.28 % self-discharge rate.

Metal–organic frameworks (MOFs) are network-like frameworks composed of transition metals and organic ligands containing oxygen or nitrogen. Because of its highly controllable composition and ordered porous structure, it has broad application prospects in the field of material synthesis. In this work, Zn4( PYDC)4(DMF)2∙3DMF (ZPD) was synthesized via a hydrothermal method. Self-doped nitrogen porous carbon ZPDC-T was then prepared by one-step carbonization. The results show that the self-doped nitrogen porous carbon ZPDC-850 has a micro/mesoporous structure with a specific surface area of 1520 m2 g− 1 and a nitrogen content of 6.47%. When a current density is 1.0 A g− 1, its specific capacitance is 265.1 F g− 1. After 5000 times of constant current charging and discharging, the capacitance retention rate was 79.2%. Thus, self-doped nitrogen porous carbon ZPDC-850 exhibits excellent electrochemical properties and good cyclic stability. Therefore, the self-doped nitrogen porous carbon derived from MOFs can be a promising electrode material for supercapacitors.

Nanoporous carbon/MnO2 (C–MnO2) composites with foam-like structure based on modified nitrile butadiene rubber were achieved by thermal treatment, followed by alkaline solution etching and dipping method. The XRD, nitrogen adsorption and desorption, and SEM and TEM were used to characterize the microstructure of the obtained C–SiO2, C and C–MnO2. Finally, all the obtained samples have been used in three-electrode system to study the electrochemical properties including cyclic voltammetry, galvanostatic charge/discharge and AC impedance for supercapacitor. The study found that the specific capacity of C–MnO2 electrode material for supercapacitor could reach as high as 109 F/g under the current density of 0.5 A/g, which is much higher than those of the other two. These superior electrochemical properties are attributed to the synergistic effect MnO2 particles with the C matrix which functions as a conductive support.

The self-discharge behavior of zinc-air batteries is a critical issue induced by corrosion and hydrogen evolution reaction (HER) of zinc anode. The corrosion reaction and HER can be controlled by a gelling agent and concentration of potassium hydroxide (KOH) solution. Various concentrations of KOH solution and polyacrylic acid have been used for gel electrolyte. The electrolyte solution is prepared with different concentrations of KOH (6 M, 7 M, 8 M, 9 M). Among studied materials, the cell assembled with 6 M KOH gel electrolyte exhibits the highest specific discharge capacity and poor capacity retention. Whereas, 9 M KOH gel electrolyte shows high capacity retention. However, a large amount of hydrogen gas is evolved with 9 M KOH solution. In general, the increase in concentration is related to ionic conductivity. At concentrations above 7 M, the viscosity increases and the conductivity decreases. As a result, compared to other studied materials, 7 M KOH gel electrolyte is suitable for Zn-air batteries because of its higher capacity retention (92.00 %) and specific discharge capacity (351.80 mAh/g) after 6 hr storage.

큰 치환기를 갖는 새로운 이온형 폴리아세틸렌 유도체인 폴리(2-에티닐-N-아이오도피리디늄 테트라 페닐보레이트)를 소듐 테트라페닐보레이트를 사용한 폴리(2-에티닐-N-아이오도피리디늄 아이오다이드)의 이온 교환반응으로 합성하였다. 합성한 폴리(2-에티닐-N-아이오도피리디늄 테트라페닐보레이트)의 전자-광 및 전기 화학적 특성을 연구하였다. 합성 고분자의 UV-visible 스펙트럼에서는 공액구조 고분자의 특징인 800 nm까지 의 장파장 영역에서 공액구조 고분자의 특징적인 흡수 피크를 보여주었다. 고분자의 사이클릭 볼타모그램은 산화와 환원 피크사이에서 안정한 비가역적 전기화학적 거동을 보였다.

Layered LiNi0.83Co0.11Mn0.06O2 cathode materials single- and dual-doped by the rare-earth elements Ce and Nd are successfully fabricated by using a coprecipitation-assisted solid-phase method. For comparison purposes, nondoping pristine LiNi0.83Co0.11Mn0.06O2 cathode material is also prepared using the same method. The crystal structure, morphology, and electrochemical performances are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) mapping, and electrochemical techniques. The XRD data demonstrates that all prepared samples maintain a typical α-NaFeO2-layered structure with the R-3m space group, and that the doped samples with Ce and/or Nd have lower cation mixing than that of pristine samples without doping. The results of SEM and EDS show that doped elements are uniformly distributed in all samples. The electrochemical performances of all doped samples are better than those of pristine samples without doping. In addition, the Ce/Nd dualdoped cathode material shows the best cycling performance and the least capacity loss. At a 10 C-rate, the electrodes of Ce/Nd dual-doped cathode material exhibit good capacity retention of 72.7, 58.5, and 45.2% after 100, 200, and 300 cycles, respectively, compared to those of pristine samples without doping (24.4, 11.1, and 8.0%).

In anion exchange membrane fuel cells, Pd nanoparticles are extensively studied as promising non-Pt catalysts due to their electronic structure similar to Pt. In this study, to fabricate Pd nanoparticles well dispersed on carbon support materials, we propose a synthetic strategy using mixed organic ligands with different chemical structures and functions. Simultaneously to control the Pd particle size and dispersion, a ligand mixture composed of oleylamine(OA) and trioctylphosphine(TOP) is utilized during thermal decomposition of Pd precursors. In the ligand mixture, OA serves mainly as a reducing agent rather than a stabilizer since TOP, which has a bulky structure, more strongly interacts with the Pd metal surface as a stabilizer compared to OA. The specific roles of OA and TOP in the Pd nanoparticle synthesis are studied according to the mixture composition, and the oxygen reduction reaction(ORR) activity and durability of highly-dispersed Pd nanocatalysts with different particles sizes are investigated. The results of this study confirm that the Pd nanocatalyst with large particles has high durability compared to the nanocatalyst with small Pd nanoparticles during the accelerated degradation tests although they initially indicated similar ORR performance.

We have synthesized new alkylated indenopyrazine homopolymer and its copolymer having an alkylated spirofluorene moiety. Poly(6,6,12,12-(Tetra-2-ethylhexyl)-6,12-Dihydrodiindeno[1,2-b:1,2-e]pyrazine-2,8-diyl) [PEHIP] and Poly(6,6,12,12-(tetra-2-ethylhexyl)-6,12-dihydrodiindeno[1,2-b:1,2-e]pyrazine-co-20,30,60,70-tertrakis-octyloxy-9-spirofluorene) [PEHIPSF] were polymerized by using Yamamoto reaction. PEHIP and PEHIPSF showed the PL maximum values of 470 nm and 454 nm in PL spectra. The PEHIPSF was fabricated into an EL device and it exhibited the EL maximum value of 463 nm.