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Li/S battery has high potential for large scale batteries due to their high theoretical energy density. For high practical energy density of Li/S batteries, a method for synthesizing a new electrode structure should be developed. We demonstrate the development of low-cost Li/S batteries via the simple synthesis of sulfurized polyacrylonitrile (S-PAN) using a glass casting and heating method. The optimum conditions for electrode synthesis were determined using various precursor ratios. Structural characterization of the S-PAN electrodes was performed through scanning electron microscope, X-ray diffractometer, and elemental analysis. At the molecular scale, the S-PAN particles are connected to each other through π-conjugated structures. Furthermore, the electrodes possess high internal porosity, which improves the Li+ ion mobility through enhanced electrolyte uptake. The S-PAN electrodes synthesized using an S:PAN ratio of 5:1 exhibited the best practical capacity after 30 cycles (327 mAh g−1-electrode, 1065 mAh g−1-S). Significantly, the impressive capacity and cyclability of the S-PAN cathode are achieved without using a binder or conducting agents. Therefore, glass-cast S-PAN represents a simple, low-cost approach for synthesizing Li/S batteries with improved capacity.

Transition metal oxide materials with high theoretical capacities have been studied as substitutes for commercial graphite in lithiumion batteries. Among these, SnO2 is a promising alloying reaction-based anode material. However, the problem of rapid capacity fading in SnO2 due to volume variation during the alloying/dealloying processes must be solved. The lithiation of SnO2 results in the formation of a Li2O matrix. Herein, the volume variation of SnO2 was suppressed by controlling the voltage window to 1 V to prevent the delithiation reaction between Li2O and Sn. Using this strategy the unreacted Li2O matrix was enriched with metallic Sn particles, thereby providing a pathway for lithium ions. The specific capacity decay in the voltage window of 0.05–3 V was 1.8% per cycle. However, the specific capacity decay was improved to 0.04% per cycle after the voltage window was restricted (in the range of 0.05–1 V). This strategy resulted in a specific capacity of 374.7 mAh g−1 at 0.1 C after 40 cycles for the SnO2 anode.

In this work, the hydrothermal method was employed to produce SnO2/rGO as anode material. Nanostructured SnO2 was prepared to enhance reversibility and to deal with the undesirable volume changes during cycling. The SnO2/rGO hybrid exhibits long cycle life in lithium-ion storage capacity and rate capability with an initial discharge capacity of 1327 mAh/g at 0.1 C rate. These results demonstrate that a fabricated SnO2/rGO matrix will be a possible way to obtain high rate performance.

Owing to the speculated price hike and scarcity of lithium resources, sodium-ion batteries are attracting significant research interest these days. However, sodium-ion battery anodes do not deliver good electrochemical performance, particularly rate performance. Herein, we report the facile electrospinning synthesis of a free-standing nickel disulfide (NiS2) embedded on carbon nanofiber. This electrode did not require a conducting agent, current collector, and binder, and typically delivered high capacity and rate performance. The electrode delivered a high initial capacity of 603 mAh g−1 at the current density of 500 mA g−1. Moreover, the electrode delivered the capacity of 271 mAh g−1 at the high current density of 15 A g−1. The excellent rate performance and high coulombic efficiency of the electrode were attributed to its low charge transfer resistance and unique structure.

Sulfurized polyacrylonitrile (S-PAN) is one of the best materials for addressing some of the intrinsic drawbacks of lithium–sulfur batteries, such as the intrinsic insulating properties of sulfur and the shuttle phenomenon. Moreover, while S-PAN nanofiber composites are flexible, they still presents shortcomings, such as low rate capability, which is due to their semiconductor electrical conductivity. In this study, we prepared S-PAN webs with high electrical conductivity via electrospinning using conducting agents. Additionally, we analyzed the electrochemical properties of the S-PAN webs prepared using various conducting agents (acetylene black, Ketjen black, and multi-walled carbon nanotubes). The specific capacity of the S-PAN web prepared using acetylene black was 740 mAh g–1 at the charge rate of 5 C. The excellent rate capability of S-PAN prepared using acetylene black was attributed to its low electrical resistance and low charge transfer resistance.

LiNixCoyAlzO2 (NCA) is one of the most promising candidates of cathode material for lithium ion batteries because of its high capacity, energy density, and low cost. However, Ni-rich NCA cathode materials suffer from side reaction (formation of lithium carbonate and hydrogen fluoride attack) between electrolyte and surface of electrode and irreversible phase transition leading to capacity fading and thermal instability. These problems could be improved by coating and doping of transition metal elements. Si doping contributes to stabilization of the unstable R-3m structure, and Ti coating is capable of prohibiting the direct physical contact of electrode with electrolyte. In this work, LiNi0.8Co0.15Al0.05O2 (NCA) cathode materials coated or/and doped by Ti and Si elements were fabricated by co-precipitation method using the ball-milling. The crystal structure, morphology and electrochemical properties are investigated using X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), transmission electron microscopy (FE-TEM), and WBCS3000 (WonA tech Co., Ltd.). The EIS and charge/discharge results of Si doped and Ti coated NCA exhibited the lowest resistance value (147.19 Ω) and capacity retentions of 88% after 100 cycles at 0.5 C.

A highly ordered mesoporous carbon@iron disulfide (CMK-5@FeS2) composite was prepared via an in-situ impregnation and sulfurization method. The CMK-5 matrix with excellent conductivity and high surface area not only formed a continuous conductive network to improve the performance of the CMK-5@FeS2 composite, but also provided sufficient space to buffer the volume changes during cycling. The CMK-5@FeS2 cell exhibited excellent electrochemical performance. After 80 cycles, the CMK-5@FeS2 cell showed the discharge capacities of 650 and 380 mAh g–1 at 2 C and 5 C, respectively. The excellent results show that CMK-5 with unique mesoporous structure can contribute to accelerating ion transfer in the electrode due to the easy accessibility of the electrolyte, which implies CMK-5@FeS2 composite could be a promising cathode active material for rechargeable lithium ion (Li-ion) batteries.

Li[NixCoyMnz]O2 (LiNCM) is one of the candidate cathode material that can replace the currently commercialized LiCoO2 (LCO) cathode material for lithium-ion batteries (LiBs). The morphological feature having primary particle and secondary sphere particle could affect structural stability, tap density and electrochemical performance of LiNCM. In this work, two LiNCM particles without or with the morphological collapse of the secondary particles were prepared by using a co-precipitation-assisted, solid-phase method and ball milling, and its morphological, structural and electrochemical characteristics were evaluated. The results of XRD, and FESEM demonstrated that the as-prepared two LiNCMs have a typical α-NaFeO2 layered structure and the two morphological features of secondary particles needed in this study. The results of electrochemical properties indicated that the LiNCM electrode without collapsed secondary particles have a good stability in cycle performance compared to that with collapse of secondary particles at 0.5, 1.0 and 2 C-rate. The capacity retention of without and with collapsed NCM was 55.8% and 27.3% after 200 cycles at 1 C-rate, respectively.

Recently, sodium ion batteries have attracted considerable interest for large-scale electric energy storage as an alternative to lithium ion batteries. However, the development of anode materials with long cycle life, high rate, and high reversible capacity is necessary for the advancement of sodium ion batteries. Bi anode is a promising candidate for sodium ion batteries due to its high theoretical capacity (385 mAh g–1 or 3800 mAh l–1) and high electrical conductivity (7.7 × 105 S m –1). Herein, we report the preparation of Bi anode using micro-sized commercial Bi particles. DME-based electrolyte was used, which is well known for its high ionic conductivity. The Bi anode showed excellent rate-capability up to 16 C-rate, and long cycle life stability with a high reversible capacity of 354 mAh g–1 at 16 C-rate for 50 cycles.

To improve the electrochemical properties of Ni-rich LiNi0.8Co0.15Al0.05O2 (LiNCA) cathode material, Ti doped or/and Al(OH)3 coated were by co-precipitation-assisted solid-phase and ball milling method was employed in this work. The morphology, structure, and electrochemical performance of the cathode materials were evaluated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectrometer (EDS), field emission transmission electron microscopy (FETEM) and electrochemical techniques. Ti doping is introduced into the octahedral lattice space occupied by Li-ions to widen the Li layer spacing and thereby increase the lithium diffusion kinetics. The Al(OH)3 coating also formed a non-uniform layer on the outside of LiNCA, thereby inhibiting side reactions between the electrode and the electrolyte. As a result, the LiNCA electrode showed a high initial discharge capacity of 167.4 mAh/g. However, after 100 cycles, it showed poor cycling stability of 41.7%. In contrast, Ti doped and Al(OH)3 coated LiNCA showed the best cycling stability of 82.2% after 100 cycles.

Tin-based materials, due to their high theoretical capacity of 994 mAh g-1 are potential candidates which can substitute the commercialized graphite anodes (372 mAh g-1). However, practical usage of pure tin in Li-ion cells has been hampered by the tremendous volume expansion of more than 260% during the lithium insertion/extraction process, resulting in particle pulverization and electrical disconnection from the current collector. In order to overcome this shortcoming, Sn/Cu6Sn5/C composites in this work were prepared by using pulsed wire explosion in a liquid medium and subsequently in situ polymerization. For comparison, Sn/C composite without tin-copper chemical compounds are also fabricated under a similar process. The Sn/Cu6Sn5/C and Sn/C composites were used as anodes for lithium-ion batteries. The Sn/Cu6Sn5/C composite anode showed good cyclability (scalability) and was maintained up to a capacity of 430 mAh g-1 after 100 cycles at 1 C-rate. The rate capability of the Sn/Cu6Sn5/C composite anode also showed higher performance (280 mAh g-1) than that (200 mAh g-1) of Sn/C composite at the 5 C-rate.

The microstructure and corrosion properties of as-cast AZ61 (Mg-6%Al-1%Zn) and AZ61 alloys doped with titanium and calcium and subjected to high ratio differential speed rolling were investigated. Addition of the alloying elements to the AZ61 alloy resulted in remarkable modification of the morphology and the amount of continuous β (Mg17Al12)-phase. Addition of Ti to the as-cast AZ61 alloy causes a decrease in the volume fraction (or discontinuity of the β-phase), leading to strong anodic dissolution. In contrast, addition of Ca to the as-cast AZ61 alloy is rather effective for preventing pitting corrosion. This is attributed to the formation of a semi-continuous network β-structure. The (Mg, Al)4Ca phases dispersed between the β (Mg17Al12)-phases led to continuity in the AZ61 alloy with Ca. The AZ61 and AZ61-X(Ca, Ti) alloys subjected to severe plastic deformation via high-ratio differential speed rolling possessed a nano-composite-like microstructure in which the α-Mg matrix with an ultra-fine grain was surrounded by a large number of fine β particles. These particles were either dynamically precipitated or broken at the grain boundaries, as well as in the grain interiors, by the high ratio differential speed rolling process. The corrosion resistance of the AZ61 and AZ61-X (X = Ca, Ti) alloys subjected to high ratio differential speed rolling was largely improved by the microstructural modification. The high ratio differential speed rolling process greatly influenced the texture of the Mg alloys, which significantly affected their corrosion behavior.

Recently, tin oxide (SnO2) has received significant attention for use as an anode material for next generation lithium-ion batteries (LIBs) owing to its high theoretical capacity (782 mAh g-1), which is more than twice of that of the commercialized graphite (372 mAh g-1). Several additional advantages, such as low cost, environmental friendliness, easy fabrication and natural abundance improve its promise. Although the theoretical capacity of SnO2 is high, volume expansion during cycling causes issue with cycling stability. In this study, an ordered mesoporous SnO2 was synthesized using a hard template (SBA-15), such that its mesoporous structure can buffer SnO2 particles from cracks caused by volume expansion. It can also allow effective electrolyte infiltration to ensure better reactivity of the active material with Li+ ions. The capacity of synthesized mesoporous SnO2 improved to 218.4 mAh g-1 compared regular SnO2 nanoparticles (69.6 mAh g-1) after 50 cycles at a rate of 0.1 C. Furthermore, carbon-coated mesoporous SnO2 enhanced capacity retention upon cycling (844.6 mAh g-1 after 50 cycles at 0.1 C) by insulating and preventing the cracking of the active material during lithiation and delithiation.

Various physical, chemical and mechanical methods, such as inert gas condensation, chemical vapor condensation, sol-gel, pulsed wire evaporation, evaporation technique, and mechanical alloying, have been used to synthesize nanoparticles. Among them, chemical vapor condensation (CVC) has the benefit of its applicability to almost all materials because a wide range of precursors are available for large-scale production with a non-agglomerated state. In this work, Fe nanoparticles and nanowires were synthesized by chemical vapor condensation method using iron pentacarbonyl (Fe(CO)5) as the precursor. The effect of processing parameters on the microstructure, size and morphology of Fe nanoparticles and nanowires were studied. In particular, we investigated close correlation of size and morphology of Fe nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. The atomic quantity was calculated by Boyle's ideal gas law. The Fe nanoparticles and nanowires with various diameter and morphology have successfully been synthesized by the chemical vapor condensation method.

Carbon nanotubes (CNTs) were purified using acid solution, and CNT-sulfur composite powder was prepared via precipitation, using the purified CNTs. In addition, the effect of the purified CNTs (PUCNTs) on the electrochemical performance of the Li/S cell was investigated. After the purification, almost all the impurities in the as-synthesized CNTs (ASCNTs) were removed, and the dispersibility of the CNTs was improved. On the other hand, the concentration of the structural defects and of the disordered structures in the PUCNTs was increased due to the surface oxidation of the tubes during acid treatment. In the case of the PUCNT-S composite powder, the outer wall of the tubes was well covered with sulfur, as opposed to the tubes in the ASCNT-S composite powder. The Li/S cell containing ASCNT-S composite cathode showed a large voltage decrease and a 680 mAh/g capacity during the first discharge process. The Li/S cell with PUCNT-S composite cathode, however, showed a higher discharge capacity and better cycle performance than the cell with ASCNT-S composite cathode. The electrochemical performance of the Li/S cell was improved for the PUCNT-S composite cathode using the CNTs purified by acid treatment.

High purity and single crystalline beta-Ga2O3 nanomaterials with various morphologies were obtained through the simple thermal evaporation of metal gallium powder on a gold-coated silicon substrate in argon. In this report, the growth behavior of the beta-Ga2O3 nanomaterials as a function of synthesis time and source material supply was delicately surveyed via FESEM and HRTEM. The synthesis time and source material supply affected morphology, growth rate and growth mechanism of the grown nanomaterials. It was confirmed that the growth mechanism of the beta-Ga2O3 nanomaterials was varied in the order of VLS, combination of VLS and VS, and VS, by increasing the synthesis time without regard to the supply of the source material. When the source materials supply was increased, many beta-Ga2O3 nanomaterials with various morphologies, such as sheet, triangle, and belt-like were appeared. It was confirmed that the oxidation reaction of gallium and oxygen for the formation of gallium oxide nanomaterials carried out the precipitation of gallium at the same time due to the supersaturation of the gallium atoms in gold catalyst. The growth and formation mechanism of the beta-Ga2O3 nanomaterials are discussed herein.