• Korean Journal of Materials Research
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• v.12 no.11
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• pp.860-864
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• 2002

$Li^{+}$ extraction reactions with ion-exchange type lithium manganese oxide in an aqueous phase were examined using chemical and x-ray diffraction (XRD) analysis. In the process of extraction reaction, the lithium manganese oxide showed a topotactic extraction of $Li^{+ }$ in the aqueous phase mainly through an ion-exchange mechanism, and the $Li^{+}$ extracted samples indicated a high selectivity and a large capacity for $Li^{+}$ . The electronic structures and chemical bonding properties were also studied using a discrete variational (DV)-X$\alpha$ molecular orbital method with cluster model of (Li$Mn_{12}$ $O_{40}$ )$^{27-}$ for tetrahedral sites and ($Li_{7}$ Mn $O_{38}$ )$^{3}$ for octahedral site in $Li_{1.33}$ $Mn_{1.67}$ / $O_{4}$ respectively. Li in the manganese oxides is highly ionized in both sites, but the net charge of Li was greater for tetrahedral sites than octahedral. These calculations suggest that the tetrahedral sites have higher $Li^{+}$ $H^{+}$ exchangeability than the octahedral sites, and are preferable for the selective adsorption for L $i^{+}$ ions.s.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.588-593
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• 2006

Spinel phase $LiMn_2O_4$ is of great interest as cathode materials for lithium-ion batteries. In this study, SHS (Self propagating High-temperature Synthesis) method to synthesize spinel $LiMn_2O_4$ directly from lithium nitrate, manganese oxide, manganese and sodium chloride were investigated. The influence of Li/Mn ratio, the heat-treated condition of product have been explored. The resultant $LiMn_2O_4$ synthesized under the optimum synthesis conditions shows perfect spinel structure, uniform particle size and excellent electrochemical performances.

• Journal of the Korean institute of surface engineering
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• v.37 no.5
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• pp.301-306
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• 2004

Electric Conductivities of $LaCl_3$-LiCl binary melts have been measured by the Kohlausch bridge method over the range of their liquidus temperatures to about 1200 K. The electric conductivity increases with the content of LiCl for all over the composition range of binary melts. Composition dependence of the electric conductivity and molar conductivity for the binary melt shows a non-linear relation from the additivity line, and the deviations displays a maximum value at about 60 mol % LiCl. This suggest the existence of the complex ion of$ LaCl_{4}^{-}$ in the melt. Activation energy for electric conductivity of the binary melts decrease monotonously with increasing content of LiCl.l.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1220-1221
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• 2006

[ $LiMn_2O_4$ ] powders for lithium ion batteries were synthesized from two separate raw material pairs of LiOH/MnO and $LiOH/MnO_2$. The powders prepared at 780 and $850^{\circ}C$ and their difference of electrochemical properties were investigated. Both powders calcined at 780 and $850^{\circ}C$ were composed of a single-phase spinel structure but those treated at $850^{\circ}C$ showed a lower intensity ratio of $I_{311}$ to $I_{400}$, a slightly larger lattice parameter, and an increased discharge capacity by 10% under $3.0{\sim}4.3V$ voltage range. The XPS study on the oxidation states of manganese repealed that powders made from LiOH/MnO had less $Mn^{3+}$ ion and gave better battery performances than those from $LiOH/MnO_2$.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.424-430
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• 2021

The element iron (Fe) is affordable and abundantly available, and thus, it finds use in a wide range of applications. As regards its application in rechargeable lithium-ion batteries (LIBs), the electrochemical reactions of Fe must be clearly understood during battery charging and discharging with the LIB electrolyte. In this study, we conducted systematic electrochemical analyses under various voltage conditions to determine the voltage at which Fe corrosion begins in general lithium salts and organic solvents used in LIBs. During cyclic voltammetry (CV) experiments, we observed a large corrosion current above 4.0 V (vs. Li/Li⁺). When a constant voltage of 3.7 V (vs. Li/Li⁺), was applied, the current did not increase significantly at the beginning, similar to the CV scenario; on the other hand, at a voltage of 3.8 V (vs. Li/Li⁺), the current increased rapidly. The impact of this difference was visually confirmed via scanning electron microscopy and optical microscopy. Our X-ray photoelectron spectroscopy measurements showed that at 3.7 V, a thick organic solid electrolyte interphase (SEI) was formed atop a thin fluoride SEI, which means that at ≥3.8 V, the SEI cannot prevent Fe corrosion. This result confirms that Fe corrosion begins at 3.7 V, beyond which Fe is easily corrodible.

• Corrosion Science and Technology
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• v.22 no.6
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• pp.466-477
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• 2023

The increasing demand for high-performance energy storage systems has highlighted the limitations of conventional Li-ion batteries (LIBs), particularly regarding safety and energy density. All-solid-state batteries (ASSBs) have emerged as a promising next-generation energy storage system, offering the potential to address these issues. By employing nonflammable solid electrolytes and utilizing high-capacity electrode materials, ASSBs have demonstrated improved safety and energy density. Automotive and energy storage industries, in particular, have recognized the significance of advancing ASSB technology. Although the use of Li metal as ASSB anode is promising due to its high theoretical capacity and the expectation that Li dendrites will not form in solid electrolytes, persistent problems with Li dendrite formation during cycling remain. Therefore, the exploration of novel high-performance anode materials for ASSBs is highly important. Recent research has focused extensively on alloy-based anodes for ASSBs, owing to their advantages of no dendrite formation and high-energy density. This study provides a comprehensive review of the latest advancements and challenges associated with alloy-based anodes for ASSBs.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.282-287
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• 2016

This study involves enhancing the performance of the $Na(Li,Ti)O_2$ system as an Na-ion battery anode with the addition of Mg, which partially replaces Li ions. We perform both computational and experimental approaches to achieve a higher reversible capacity and a faster transport of Na ions for the devised system. Computational results indicate that the $Na(Li,Mg,Ti)O_2$ system can provide a lower-barrier path for Na-ion diffusion than can a system without the addition of Mg. Experimentally, we synthesize various $Na_z(Li_y,Mg_x,Ti)O_2$ systems and evaluate their electrochemical characteristics. In agreement with the theoretical study, Mg addition to such systems improves general cell performance. For example, the prepared $Na_{0.646}(Li_{0.207}Mg_{0.013}Ti_{0.78})O_2$ system displays an increase in reversible capacity of 8.5% and in rate performance of 13.5%, compared to those characteristics of a system without the addition of Mg. Computational results indicate that these improvements can be attributed to the slight widening of the Na-$O_6$ layer in the presence of Mg in the $(Li,Ti)O_6$ layer.

• Journal of Electrochemical Science and Technology
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• v.9 no.1
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• pp.60-68
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• 2018

In aqueous rechargeable lithium ion batteries, $LiV_3O_8$ exhibits obviously enhanced electrochemical performance after $AlF_3$ surface modification owing to improved surface stability to fragile aqueous electrolyte. The cycle life of $LiV_3O_8$ is significantly enhanced by the presence of an $AlF_3$ coating at an optimal content of 1 wt.%. The results of powder X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and galvanostatic charge-discharge measurements confirm that the electrochemical improvement can be attributed mainly to the presence of $AlF_3$ on the surface of $LiV_3O_8$. Furthermore, the $AlF_3$ coating significantly reduces vanadium ion dissolution and surface failure by stabilizing the surface of the $LiV_3O_8$ in an aqueous electrolyte solution. The results suggest that the $AlF_3$ coating can prevent the formation of unfavorable side reaction components and facilitate lithium ion diffusion, leading to reduced surface resistance and improved surface stability compared to bare $LiV_3O_8$ and affording enhanced electrochemical performance in aqueous electrolyte solutions.

• Carbon letters
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• v.2 no.1
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• pp.72-75
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• 2001

The performance of Li-ion system based on $LiCoO_2$ and Graphite is well optimized for the 3C applications. The charge-discharge mode, the manufacturing process, the cell performance and the thermal reactions affecting safety has been explained in the engineering point of view. The energy density of the current LIB system is in the range of 300~400 Wh/l. In order to achieve the energy density higher than 500 Wh/l, the active materials should be modified or changed. Adopting new high capacity anode materials would be effective to improve energy density.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.227-228
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• 2017

In this paper, electrolytic behavior of Cerium and Ce-Bi ion system was studied. The electrochemical behavior of Ce was studied in $LiCl-KCl-CeCl_3$ molten salts using electrochemical techniques Cyclic Voltammetry on tungsten electrodes at 773K. During the process of CV electrolysis, intermetallic compound were observed of Ce, Cex-Biy. Further study, in order to determine clarity of diffusion coefficient in this experiment, we will compare result of electrochemistry method and we also need to quantitative research.