0000000000344210
AUTHOR
Juho Välikangas
showing 8 related works from this author
Co-precipitation of Mg-doped Ni0.8Co0.1Mn0.1(OH)₂:effect of magnesium doping and washing on the battery cell performance
2023
Co-precipitation of Ni0.8Co0.1Mn0.1(OH)2 (NCM811) and Mg-doped (0.25 wt% and 0.5 wt%) NCM811 precursors is carried out from concentrated metal sulphate solutions. In this paper, the aim is to study the role of magnesium dopant in the co-precipitation step of NCM811, the cathode active material and further the Li-ion battery cell performance. Based on the results, magnesium was fully co-precipitated in the NCM811 precursors, as expected from thermodynamic calculations. The presence of magnesium in these precursors was also confirmed by several characterization methods and magnesium was evenly distributed in the sample. It was observed that tapped density decreased and surface area increased …
Optimized morphology and tuning the Mn3+ content of LiNi0.5Mn1.5O4 cathode material for li-ion batteries
2023
The advantages of cobalt-free, high specific capacity, high operating voltage, low cost, and environmental friendliness of spinel LiNi0.5Mn1.5O4 (LNMO) material make it one of the most promising cathode materials for next-generation lithium-ion batteries. The disproportionation reaction of Mn3+ leads to Jahn–Teller distortion, which is the key issue in reducing the crystal structure stability and limiting the electrochemical stability of the material. In this work, single-crystal LNMO was synthesized successfully by the sol-gel method. The morphology and the Mn3+ content of the as-prepared LNMO were tuned by altering the synthesis temperature. The results demonstrated that the LNMO_11…
Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12
2016
Defect spinel phase lithium titanate (Li4Ti5O12) has been suggested as a promising negative electrode material for next generation lithium ion batteries. Flame spray pyrolysis has been shown to be a viable fast, one-step process for synthesis of nanoparticulate Li4Ti5O12. However, due to the rapid quenching that is integral to the process the crystallite size remain very small and non-uniform. To overcome this shortcoming a vertical flow tube furnace was used to increase the high-temperature residence time. This resulted in an increase in the crystallite size and crystallinity of the product. As a result of this increase the electrochemical performance of the Li4Ti5O12 was markedly improved…
Correlation of aluminum doping and lithiation temperature with electrochemical performance of LiNi1-xAlxO2 cathode material
2022
Abstract This article presents a process for producing LiNi1-xAlxO2 (0 < × < 0.05) cathode material with high capacity and enhanced cycle properties of 145 mAh/g after 600 cycles. The LiNi1-xAlxO2 (0 < × < 0.05) cathode material is prepared by mixing coprecipitated Ni(OH)2 with LiOH and Al(OH)3, followed by lithiation at temperature range of 650–710 °C, after which any residual lithium from lithiation is washed from the particle surfaces. Electrochemical performance was studied within full-cell and half-cell application; in addition, different material characterization methods were carried out to explain structure changes when certain amount of aluminum is introduced in the …
Effects of Lithium Source and Content on the Properties of Li-Rich Layered Oxide Cathode Materials
2023
Lithium-rich layered oxide (LLO) are considered high-capacity cathode materials for next-generation lithium-ion batteries. In this study, LLO cathode materials were synthesized via the hydroxide coprecipitation method followed by a two-step lithiation process using different lithium contents and lithium sources. The effects of lithium content and lithium source on structure and electrochemical performance were investigated. This study demonstrated the clear impact of Li/TM ratio on electrochemical performance. Lower Li/TM ratio reduced the irreversible capacity loss in the first cycle and provided better cycling stability among all samples. The best results exhibited an initial discharge ca…
Precipitation and Calcination of High-Capacity LiNiO2 Cathode Material for Lithium-Ion Batteries
2020
This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These a…
Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12
2016
Abstract Defect spinel phase lithium titanate (Li 4 Ti 5 O 12 ) has been suggested as a promising negative electrode material for next generation lithium ion batteries. Flame spray pyrolysis has been shown to be a viable fast, one-step process for synthesis of nanoparticulate Li 4 Ti 5 O 12 . However, due to the rapid quenching that is integral to the process the crystallite size remain very small and non-uniform. To overcome this shortcoming a vertical flow tube furnace was used to increase the high-temperature residence time. This resulted in an increase in the crystallite size and crystallinity of the product. As a result of this increase the electrochemical performance of the Li 4 Ti 5 …
Effect of Reaction Conditions on the Coprecipitation of Ni(OH)2 for Lithium-Ion Batteries
2023
Electrochemical performance of cathode active materials (CAMs) is dependent on the properties of coprecipitated precursors (pCAMs). This is a sensitive process affected by several reaction parameters such as temperature, pH, concentration of reactants, agitation rate, and residence time. In this paper, the effect of parameters influencing the particle size growth and the physical properties, such as particle morphology and tapped density, was studied in the coprecipitation of Ni(OH)2. Formation of a homogeneous population with narrow particle size distribution was observed, followed by a more heterogeneous population of dense particles. Ammonia concentration and residence time had significa…