• Journal of Powder Materials
• /
• v.21 no.2
• /
• pp.131-136
• /
• 2014

Cathode materials and their precursors are prepared with transition metal solutions recycled from the the waste lithium-ion batteries containing NCM (nickel-cobalt-manganese) cathodes by a $H_2$ and C-reduction process. The recycled transition metal sulfate solutions are used in a co-precipitation process in a CSTR reactor to obtain the transition metal hydroxide. The NCM cathode materials (Ni:Mn:Co=5:3:2) are prepared from the transition metal hydroxide by calcining with lithium carbonate. X-ray diffraction and scanning electron microscopy analyses show that the cathode material has a layered structure and particle size of about 10 ${\mu}m$. The cathode materials also exhibited a capacity of about 160 mAh/g with a retention rate of 93~96% after 100 cycles.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.7
• /
• pp.1995-2000
• /
• 2013

Layered $Li_{1.2}(Fe_{0.16}Mn_{0.32}Ni_{0.32})O_2$ was prepared by the mixed hydroxide method at various temperatures. Xray diffraction (XRD) pattern shows that this material has a ${\alpha}-NaFeO_2$ layered structure with $R{\bar{3}}m$ space group and that cation mixing is reduced with increasing synthesis temperature. Scanning electron microscopy (SEM) reveals that nano-sized $Li_{1.2}(Fe_{0.16}Mn_{0.32}Ni_{0.32})O_2$ powder has uniform particle size distribution. X-ray absorption near edge structure (XANES) analysis is used to study the local electronic structure changes around the Mn, Fe, and Ni atoms in this material. The sample prepared at $700^{\circ}C$ delivers the highest discharge capacity of 207 $mAhg^{-1}$ between 2-4.5 V at 0.1 $mAcm^{-2}$ with good capacity retention of 80% after 20 cycles.

• Tribology and Lubricants
• /
• v.1 no.1
• /
• pp.80-87
• /
• 1985

Lithium dual complex grease was prepared through the second continuous saponification reaction of a complex gellant system whose essential components comprised of a selected hydroxy fatty acid, lithium hydroxide monohydrate and boric acid to have a fiber structure of chemical, thermal and mechanical stability at high temperatures. An optimum amount of complex gellant was found to be 14% (NLGI #2), and an addition of castor wax of 1.5% provided an excellent performance properties, especially. The oil separation, oxidation stability, water wash-out property, shear stability, extreme pressure and wear property of thus prepared were tested by the ASTM and KS methods, and a characteristic result was obtained.

• Journal of Powder Materials
• /
• v.28 no.6
• /
• pp.497-501
• /
• 2021

Cobalt (Co) is mainly used to prepare cathode materials for lithium-ion batteries (LIBs) and binder metals for WC-Co hard metals. Developing an effective method for recovering Co from WC-Co waste sludge is of immense significance. In this study, Co is extracted from waste cemented carbide soft scrap via mechanochemical milling. The leaching ratio of Co reaches approximately 93%, and the leached solution, from which impurities except nickel are removed by pH titration, exhibits a purity of approximately 97%. The titrated aqueous Co salts are precipitated using oxalic acid and hydroxide precipitation, and the effects of the precipitating agent (oxalic acid and hydroxide) on the cobalt microstructure are investigated. It is confirmed that the type of Co compound and the crystal growth direction change according to the precipitation method, both of which affect the microstructure of the cobalt powders. This novel mechanochemical process is of significant importance for the recovery of Co from waste WC-Co hard metal. The recycled Co can be applied as a cemented carbide binder or a cathode material for lithium secondary batteries.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.433-436
• /
• 2008

Deterioration in the concrete structure are due to carbonation, chloride ion attack and frost attack. Therefore, concrete structure is needed to surface protection for increase durability using silicate impregnants. Thus, this study is concerned with self-cleaning and durability of silicate hydrophilic impregnants of concrete structure using lithium and potassium silicates. From the experimental test results, lithium and potassium silicates have a good properties as a carbonation resistance. Lithium and potassium silicates make good use of hydrophilic impregnants of concrete structures.

• Journal of Powder Materials
• /
• v.31 no.2
• /
• pp.163-168
• /
• 2024

As the demand for lithium-ion batteries for electric vehicles is increasing, it is important to recover valuable metals from waste lithium-ion batteries. In this study, the effects of gas flow rate and hydrogen partial pressure on hydrogen reduction of NCM-based lithium-ion battery cathode materials were investigated. As the gas flow rate and hydrogen partial pressure increased, the weight loss rate increased significantly from the beginning of the reaction due to the reduction of NiO and CoO by hydrogen. At 700 ℃ and hydrogen partial pressure above 0.5 atm, Ni and Li₂O were produced by hydrogen reduction. From the reduction product and Li recovery rate, the hydrogen reduction of NCM-based cathode materials was significantly affected by hydrogen partial pressure. The Li compounds recovered from the solution after water leaching of the reduction products were LiOH, LiOH·H₂O, and Li₂CO₃, with about 0.02 wt% Al as an impurity.

• Journal of the Korean Ceramic Society
• /
• v.18 no.2
• /
• pp.91-98
• /
• 1981

Synthetic zeolite A was prerared from domestic Hadong kaolin with sodium hydroxide solution and their ion exchange isotherms of $K^+$, $NH^{4+}$, $Li^+$ and $Ag^+$ ion were presented. The optimum reaction conditions for synthetic zeolite A from calcinated kaolin were 2 fold excess of 2N sodium hydroxide solution, 10$0^{\circ}C$ and 8 hours. It was observed that before the crystallization of zeolite A the samples reacted with sodium hydroxide solution had rather higher ion exchange capacities than zeolite A. The $K^+$-$Na^+$ and $Ag^+$$Na^+$ ion exchange isotherms were signoidal. The initial selectivity series was in the order $Ag^+$$K^+$>$Na^+$>$NH_4$>$Li^+$. Between approximately 33 and 67% replacement of soium ions the selectivity series became $Na^>$ and above 67% became $Ag^+$>$K^+$. Evidence were also presented to demonstrate that 8 out of 12 sodium ions per pseudo unit cell were not easily replaceable by lithium ions and 4 out of 12 not easily replaceable by ammonium ions.

• Resources Recycling
• /
• v.33 no.1
• /
• pp.15-21
• /
• 2024

The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H₂O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.429-429
• /
• 2008

Li$[Ni_{1/2}Co_{1/2}]O_2$ powder were synthesized from co-precipitation spherical metal oxide, $[Ni_{1/2}Co_{1/2}](OH)_2$. The preparation of metal hydroxide was significantly dependent on synthetic conditions, such as pH, amount of chelating agent, stirring speed, etc. The optimized condition resulted in $[Ni_{1/2}Co_{1/2}](OH)_2$, of which the particle size distribution was uniform and the particle shape was spherical, as observed by scanning electron microscopy. Calcination of the uniform metal hydroxide with LiOH at higher temperature led to a well-ordered layer-structured Li$[Ni_{1/2}Co_{1/2}]O_2$, as confirmed by X-ray diffraction pattern. Also these materials have ${\alpha}-NaFeO_2$ ($R\bar{3}m$) structure. Due to the homogeneity of the metal hydroxide, $[Ni_{1/2}Co_{1/2}](OH)_2$, the final product, Li$[Ni_{1/2}Co_{1/2}]O_2$, was also significantly uniform, i.e., the average particle size was of about 10 to 15 ${\mu}m$ in diameter and the distribution was relatively narrow. As a result, the corresponding tap-density was also high approximately 2.41 $gcm^{-3}$, of which the value is comparable to that of commercialized $LiCoO_2$.

• Resources Recycling
• /
• v.11 no.3
• /
• pp.10-16
• /
• 2002

In the leaching of $LiCoO_2$with a strong acid such as sulfuric and nitric acid, an additional step was needed to recover cobalt and lithium separately from spent lithium ion batteries (LIBs). The leaching of $LiCoO_2$in an oxalic acid solution was investigated to recover cobalt selectively using a low solubility of cobalt oxalate at low pH. Leaching efficiency of 95% of lithium and less than 1% of cobalt were obtained when pure $LiCoO_2$powder was leached in 3M oxalic acid at $80^{\circ}C$ and 50 g/L pulpdensity. Under the above leaching conditions, complete dissolution of lithium was accomplished with mere 0.25% of cobalt in the solution when the cathodic active material collected from spent LIBs was employed. The lithium in the leaching solution can be recovered as a form of carbonate or hydroxide depending on the addition of $Na_2$$CO_3$or LiOH.