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Numerous studies have addressed the commercial viability of lithium–air batteries (LABs). However, the high reactivity of Li with air moisture and CO2 has hindered the broad applicability of LABs. In this study, lithium-protective hybrid lithium–air batteries (HLABs) were fabricated with Super P (SP) and composites of fluorinated carbon (CFx), MoS2, and WS2 as the cathodes. Subsequently, their potential use as a power source for the next generation of defense technologies was investigated. It was observed that a single cell HLAB with the SP-CFx composite cathode exhibited a specific capacity of 893 mAhg−1cathode. In comparison, a Tomcell with the SP cathode demonstrated a specific capacity of 465 mAhg−1cathode when discharged. The cells with SP-MoS2 and SP-WS2 cathode yielded specific capacities of 357 and 386 mAhg−1cathode, respectively. The improved performance of the SP-CFx cell can be attributed to synergistic effects of lithium–air cell and lithium battery reactions between CFx and SP. To assess all functionalities of the SP-CFx HLAB, lithium-protective HLABs were fabricated and discharged in air. To operate the lithium–air battery in air, pure lithium metal was sealed with solid electrodes (lithium-ion conducting glass–ceramics (LICGC)) and a buffer electrolyte (1 M LiFTSI in TEGDME) was applied. The SP-CFx cell was discharged for 25 days in air, greatly exceeding the 72 h requirement for the next-generation soldier power systems. These results demonstrate significant potential for HLABs to be used as a pioneering power source in next-generation energy-independent tactical defense units.

The adsorption, formation, and interaction energies between carbon dioxide (CO2) and carbon oxide functional groups on porous carbon surface were analyzed through XPS, textural analysis, CO2 gas adsorption, and theoretical study. Carbon molecular sieves (CMSs) as porous carbon were modified by several concentrations of hydrogen peroxide (H2O2) solution under atmospheric conditions in an attempt to introduce carbon oxide groups and increase their CO2 adsorption capacity. Created oxide groups on carbon surface of CMSs were determined by XPS analysis and the CO2 adsorption capacities were investigated through the CO2 adsorption isotherms at 273 and 298 K at low pressure (max. 800 mmHg). The CO2 uptake capacity on CMSs modified by H2O2 was increased compared to an unmodified CMS and increased with increasing carboxylic (-COOH) group concentration on the carbon surface of CMSs. For a theoretical approach, binding energies between CO2 and various functional groups on the surface of CMSs have been investigated using several electronic structure calculations. As the result of the computational study by the MP2 method, a carboxylic group has the highest binding energy for CO2 (-COOH····CO2) of 4.45 kcal/mol, compared to quinone (dbndO) of 3.9, phenol (-OH) of 3.2 and lactone (-O-C=O) of 3.57 kcal/mol. This work demonstrates that introducing -COOH groups on CMS by H2O2 are a suitable modification for CO2 adsorption.

Lithium oxygen batteries have been recognized as one of the next-generation power sources, capable of supplying power for a long time even in an independent extreme environment. In spite of the theoretical advantage, Li-O2 batteries face technical and economic challenges that must be addressed to promote them as commercially variable technologies for future energy system. Above all, battery performance largely depends on the activities of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of the cathode during discharge and charge, respectively. The undesirable overpotential caused by sluggish reaction kinetics associated with the ORR and OER greatly limit the current performance of Li-O2 batteries, which must be improved by efficient catalyzing the reactions. Among the numerous catalysts, perovskite oxides have attention for candidate electro catalyst for Li-O2 batteries due to their high electronic/ionic conductivity, high electrochemical stability, and catalytic activity. Especially, La0.6Sr0.4Co0.2Fe0.8O3(LSCF) is considered as a typical catalyst for Li-O2 batteries, which can provide high oxygen surface exchange coefficient for fast kinetics at the gas/electrode interface. The surface area is significantly related on the ORR and OER performance, which influences on the active area for reactions. In this study, we have tried to utilize a simple high energy ball milling process to investigate the electrochemical properties of LSCF catalyst. Through the BET analysis, it was confirmed that the specific area significantly was increased after ball milling due to the reduced particle size, obtaining the optimized milling time with the higher ORR performance. The electrochemical activities have been measured with rotating disk electrode (RRDE) method. Well-ball milled LSCF catalyst has resulted in the enlargement of specific surface area and increased defective sites, which improve the catalytic activity. To investigate the influence of LSCF oxides on the ORR process, the performance of composite electrode with LSCF catalyst in LITFSI in ether solvents has been compared with a carbon based cathode (carbon nano tube(CM130)). From the discharge results, the composite electrode showed the superior performance as well as higher specific capacitance (more than 1.6 times) than carbon based electrode dye to the altered transport and reaction kinetics due to LSCF. In this study, we have proposed the processes of obtaining a catalyst with optimal electrochemical properties through a relatively simple process and applied it to electrode for lithium oxygen batteries.

Micro/meso-porous reduced graphite oxide (MMRGO) nanosheets were produced using precursor carbide-derived carbon (CDC), which was produced at a high temperature of 1200 °C, through a massive wet chemistry synthetic route involving graphite oxidation and microwave reduction. X-ray diffraction (XRD) and transmission electron microscopy (TEM) show that the MMRGO nanosheets were fabricated with 2–3 layers and ripple-like corrugations. N2 sorption isotherms confirmed that micro/meso-pores coexisted in the RGO sample from CDC. In the anode application of Li-ion batteries, this RGO sample had an enhanced capacity performance at the 0.1 C rate and 1 C rate, with ∼1200 mAh g−1 at the 100th cycle and ∼1000 mAh g−1 at the 200th cycle, respectively.

In this study, effects of pyrite () particle sizes on the electrochemical characteristics of thermal batteries are investigated using unit cells made of pulverized pyrite by ball-milling. At unit cell discharge test, the electrochemical capacity of pyrite-cell largely increases compared to pyrite-cell, and their internal resistances also decrease. These results are attributed to the increase in the active reaction area of pyrite by ball milling. However, at unit cell discharge test, a pyrite cell shows lower internal resistance than that of pyrite cell only at Z-phase region (). After that, a pyrite cell shows a decrease in the cell voltage and an rapid increase of the internal resistance in J-phase region () is observed compared to those of pyrite cell. It can be concluded that at the higher temperature, the thermally unstable pulverized pyrite is decomposed thermally as well as self discharged, simultaneously, which causes the higher resistance and lower capacity at in J-phase than that of pyrite cell.

Microstructure and thermal stability of mechanically ball milled were investigated. The average particle size and distribution of powder were changed in two steps with the increased ball milling time. The average particle size drastically decreased from to 1.01 and after ball milling of 10 h and 30 h, respectively. However, the distribution was broad and a shoulder appeared at because the pulverization was still in process at 10 h ball milling. After 60 h ball milling, the distribution became narrower. After ball milling of 120 h, the average particle size increased because of particle agglomeration. Therefore, the particle size distribution became broaden again. Finally, after ball milling of 170 h, with the narrowest size distribution can be obtained. Thermal stability of was unstable as the particle was pulverized. Therefore, the activation energy of the fine size particles is 27% lower than that of the as-received .

To improve the electrochemical performance of an activated carbon (AC)-based electric double-layer capacitor (EDLC), the AC surface, which is used as an electrode, was modified using different concentrations of phosphoric acid. The effects of the treatment on the surface and electrochemical properties of the AC electrodes were investigated. The specific capacitance increased from 256 F/g for an untreated sample to 452 F/g for a sample treated with a 2 M solution at a scan rate of 5 mV/s. This increase can be attributed to an increase in the mesopore volume caused by the etching effect of the reaction between the carbon surfaces and phosphoric acid. In addition, oxygen functional groups, which were introduced by the treatment, improved the electrochemical properties of the resulting AC-based electrode. Therefore, simultaneous etching and oxygen introduction with phosphoric acid can easily bind oxygen functional groups (particularly C O) onto the surface of an AC electrode. This method is effective at preparing AC for use in an EDLC with improved electrochemical properties.

In this study, the breakthrough curve behaviors of aminated carbon molecular sieves (CMSs) were investigated for a CO2/CH4 mixed gas, and the selective separation of CO2 was demonstrated. Nitrogen functional groups were effectively introduced onto the surfaces of the a-CMSs, and they attached themselves to the pores of the CMSs as the ammonium hydroxide concentration was increased. Nitrogen functional groups on the surfaces of the aminated CMSs, such as NH2 and CN, played an important role in guiding CO2 into the micropores via the attractive forces felt by the electrons in the CO2 molecules.

The surface of carbon molecular sieves (CMSs) was fluorinated to investigate the separation behavior of CH4/CO2. The fluorination of CMSs was carried out at various F2 partial pressures to determine the effect of the F2 content. Fluorine functional groups were effectively introduced on the surface of the CMSs, and the volume of pores in the CMSs was increased due to fluorination, especially those with a diameter less than 8 A. As the fluorine partial pressure was increase, an increase in the CO2 adsorption capacity of CMSs was observed due to Lewis acid–base interactions between the functional groups of CMSs and CO2. Based on the selective CO2 adsorption results, the CO2 breakthrough with fluorinated CMS occurred at later stages of CH4/CO2 gas separation process compared to Raw-CMS. Therefore the presence of fluorine on the surfaces of CMSs affects the pore volumes of CMSs. According to the adsorption isotherms, the CO2 adsorption efficiency of CMSs was improved from 1.61 to 2.04 mmol/g at 298 K.

A glucose sensor electrode was prepared with multi-walled carbon nanotubes (MWNTs) because of its effect on surface modification through oxyfluorination. The oxyfluorination of MWNTs was carried out with F 2 :O 2 ratios of 7:3, 5:5 and 3:7, which are labeled F7O3-MWNT, F5O5-MWNT, and F3O7-MWNT, based on the oxyfluorination conditions. The hydrophilic functional groups were introduced effectively on the hydrophobic carbon surface. In addition, the amorphous area of the MWNTs was affected by oxyfluorination. The reactivity of the glucose sensor was affected by the oxyfluorination treatment and the existence of amorphous on MWNTs. The optimum O/F percentage was approximately 50%. Therefore, the oxyfluorination conditions are important with amorphous MWNTs. The sensitivity was improved based on the effects of improved interface affinity between the enzyme and the carbon electrode. In addition, the presence of an amorphous area on MWNTs seems to be beneficial for efficient glucose oxidase immobilization, which results in high-performance glucose sensing.

Lithium-impregnated metal foam anodes (LIMFAs) are fabricated and investigated. The LIMFAs are prepared by the impregnation of lithium into molten-salt-coated nickel metal foam. A single cell with the LIMFA exhibits a specific capacity of 3009 As g−1. For comparison, a single cell with a LiSi alloy anode is also discharged, demonstrating a specific capacity of 1050 As g−1. These significant improvements can be attributed to the large amount of lithium impregnated into the metal foam as well as the molten lithium holding capability of the foam. Due to their excellent electrochemical properties, LIMFAs are suitable for use in thermal batteries.

A glucose sensor electrode was prepared from electrospun spherical-type carbon materials. The glucose oxidase (GOD) enzyme was immobilized on a prepared electrode for efficient glucose sensing. The GOD immobilization was maximized by enlarged sites of carbon electrode and improved interfacial affinity between the carbon surface and the GOD achieved via physical activation and oxyfluorination, respectively. The specific surface area was enlarged significantly, by over 42 fold, through physical activation. In addition, the hydrophobic carbon surface was modified with hydrophilic functional groups by direct oxyfluorination for improved interfacial affinity between the carbon and GOD. Accordingly, the GOD immobilization improved significantly by approximately 9 fold. The glucose sensor was evaluated by amperometric measurements and cyclic voltammetry. The measured current increased with higher glucose concentrations based on the effects of the developed pore structure and the introduced hydrophilic functional groups. The enzymatic kinetics were also studied using the Lineweaver–Burk equation. The sensitivity of the glucose sensor was improved by approximately 3 fold with increased maximum current, whereas the GOD enzyme activity was diminished by efficient GOD immobilization. Conclusively, a high-performance glucose sensor was obtained using an electrospun spherical-type carbon material due to efficient GOD enzyme immobilization.

The surfaces of carbon molecular sieves (CMSs) were thermally fluorinated to adsorb water vapor. The fluorination of the CMSs was performed at various temperatures (100, 200, 300, and 400°C) to investigate the effects of the fluorine gas (F2) content on the surface properties. Fluorine-related functional groups formed were effectively generated on the surface of the CMSs via thermal fluorination process, and the total pore volume and specific surface area of the pores in the CMSs increased during the thermal fluorination process, especially those with diameters ≤ 8 Å. The water vapor adsorption capacity of the thermally fluorinated CMSs increased compared with the as-received CMSs, which is attributable to the increased specific surface area and to the semicovalent bonds of the C–F groups.

Supercapacitor have been widely researched in order to apply many fields such as a hybrid electric vehicles, high pulse power sources, and emergency power sources requiring high power instantly. However, supercapacitor has low energy density compared to batteries. In order to increase the energy density of supercapacitor, electrode is the very important. Until now, porous carbons, which have low energy density (5~10 Wh kg-1) are the widely used for electrode materials. Recently, many reports have been released using a surface treated carbon or graphene, RGO and CDC, etc. However, these ways have much time and costs in order to compensate the energy. In this study, the CO2 laser treated carbon electrode is investigated for high-performance supercapacitors. First of all, in order to investigate the effect of CO2 laser radiation on energy density and microstructure, carbon electrode was fabricated as a mixture of active material, conductive material, and PVDF binder. The mixed slurry with NMP was coated onto an aluminum plate and dried at 100 oC for 12h. And then CO2 laser was radiated onto the surface of the carbon electrode. A 2032coin cell was assembled with the TEABF4 as electrolyte and separator. The microstructure difference was investigated with SEM and cyclic voltammetry tests also were carried out in the potential range of 0 to 2.7 V for comparison to CO2 laser radiated and un-radiated carbon electrode.

A wide variety of supercapacitors has been developed for many high-power energy storage application. Especially, flexible supercapacitors with thin electrodes are being needed for powering flexible electronics for military applications. In this study, the inkjet-printed graphene electrode is investigated for high-performance thin film supercapacitors. In order to make the ink for printing, graphene flakes ware dispersed in a solvent and then printed onto a metal foil. The electrodes were inkjet-printed with the various graphene flake size and the film thickness. After the printing, the electrodes were dried to remove solvent. These electrodes were sealed together with the electrolyte and separator, and then assembled into a coin cell. The microstructures of the printed graphene electrodes were analyzed by SEM, TEM and XRD. The electrochemical performances were also investigated.

A Li-Si/FeS2 electrochemical system, which is widely used for thermal batteries, has limited energy density and power capability due to the partial utilization of the active materials. A single cell with a molten lithium anode or a molten sulfur cathode has a high energy density with a high open circuit voltage compared to that with a Li-Si/FeS2 couple. The main challenges in the molten electrodes arise from the instability of liquid active materials which can directly react with the other electrode and results in catastrophic thermal runaways, such as vent, fire or even explosion. For the practical application to thermal batteries which operates at above the melting point of the active electrode materials, the immobilization of the molten electrode is inevitably required. The combination of the porous metal foams with liquid active materials is found to be quite effective solution to attain unconventionally high energy density as well as high power capability. In this study, highly conductive nickel foam electrodes are incorporated with pure lithium or sulfur. The electrochemical characteristics are investigated along with the single cell tests and the microstructural analysis.