Nanocrystalline layer-structured monoclinic Na2Ti3O7 is currently under consideration for usage i... more Nanocrystalline layer-structured monoclinic Na2Ti3O7 is currently under consideration for usage in solid state electrolyte applications or electrochemical devices, including sodium-ion batteries, fuel cells, and sensors. Herein, a facile one-pot hydrothermal synthetic procedure is developed to prepare self-assembled moss-like hierarchical porous structure constructed by ultrathin Na2Ti3O7 nanotubes with an outer diameter of 6–9 nm, a wall thickness of 2–3 nm, and a length of several hundred nanometers. The phase and chemical transformations, optoelectronic, conductive, and electrochemical properties of as-prepared hierarchically-organized Na2Ti3O7 nanotubes have been studied. It is established that the obtained substance possesses an electrical conductivity of 3.34 × 10−4 S/cm at room temperature allowing faster motion of charge carriers. Besides, the unique hierarchical Na2Ti3O7 architecture exhibits promising cycling and rate performance as an anode material for sodium-ion batteri...
Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique. It was ... more Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique. It was found that the incorporation of 5 at.% Ni into bronze TiO2 expanded the unit cell by 4%. Furthermore, Ni dopant induced the 3d energy levels within TiO2(B) band structure and oxygen defects, narrowing the band gap from 3.28 eV (undoped) to 2.70 eV. Oppositely, Zn entered restrictedly into TiO2(B), but nonetheless, improves its electronic properties (Eg is narrowed to 3.21 eV). The conductivity of nickel- (2.24 × 10−8 S·cm−1) and zinc-containing (3.29 × 10−9 S·cm−1) TiO2(B) exceeds that of unmodified TiO2(B) (1.05 × 10−10 S·cm−1). When tested for electrochemical storage, nickel-doped mesoporous TiO2(B) nanobelts exhibited improved electrochemical performance. For lithium batteries, a reversible capacity of 173 mAh·g−1 was reached after 100 cycles at the current load of 50 mA·g−1, whereas, for unmodified and Zn-doped samples, around 140 and 151 mAh·g−1 was obtained. Moreover, Ni doping enh...
Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol... more Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol-gel method on carbon fiber. Physicochemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis, and Brunauer−Emmett−Teller measurements. It was confirmed that Hf4+ substitute in the Ti4+ sites, forming Ti1–xHfxO2 (x = 0.01; 0.03; 0.05) solid solutions with an anatase crystal structure. The Ti1–xHfxO2 materials are hollow microtubes (length of 10–100 μm, outer diameter of 1–5 μm) composed of nanoparticles (average size of 15–20 nm) with surface area of 80–90 m2 g–1 and pore volume of 0.294–0.372 cm3 g–1. The effect of hafnium ions incorporation on electrochemical behavior of anatase TiO2 as Li-ion battery anode was investigated by galvanostatic charge/discharge and electrochemical impedance spectroscopy. It was established that Ti0.95Hf0.05O2 shows significantly higher reversibility (154.2 mAh g–1) after 35-fold cycling at C/10 rate in comparison with undoped titania (55.9 mAh g–1). The better performance offered by Hf4+ substitution of the Ti4+ into anatase TiO2 mainly results from more open crystal structure, which has been achieved via the difference in ionic radius values of Ti4+ (0.604 Å) and Hf4+ (0.71 Å). The obtained results are in a strong accordance with ones for anatase TiO2 doped via Zr4+ (0.72 Å) published earlier. Furthermore, improved electrical conductivity of Hf-doped anatase TiO2 materials due to charge redistribution in the lattice and enhanced interfacial lithium storage due to increased surface area directly depending on Hf/Ti atomic ratio have beneficial effect on electrochemical properties
Гидротермальным синтезом получены нанотрубки диоксида титана со структурой бронз (TiO 2 (B)), доп... more Гидротермальным синтезом получены нанотрубки диоксида титана со структурой бронз (TiO 2 (B)), допированного ванадием. Синтезированный материал характеризуется мезопористостью и высокой удельной площадью поверхности, достигающей 180 м 2 /г. Показано, что введение ванадия в кристаллическую структуру TiO 2 (B) сопровождается увеличением объема элементарной ячейки. Для допированного диоксида титана по сравнению с недопированным зафиксировано повышение электропроводности приблизительно на три порядка вплоть до 1.70 • 10 −8 См/см. При использовании в качестве анодного материала литийионного аккумулятора V-замещенная производная TiO 2 (B) продемонстрировала улучшенные циклические и мощностные характеристики. В частности, после 100 циклов заряда/разряда в режиме 9С на электроде из допированного диоксида титана достигнута ёмкость 133 мА•ч/г с эффективностью циклирования более 98.9%. В условиях высокой токовой нагрузки 18С допированный TiO 2 (B) сохраняет обратимую ёмкость на уровне 114 мА•ч/г, что отвечает 40% от ёмкости первоначального разряда при 0.45C. Ключевые слова: литий-ионный аккумулятор, анод, TiO 2 (B), допирование, нанотрубки, мезопористость.
Journal of Materials Science & Technology, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
В работе изучен механизм влияния примеси марганца на электрохимические характеристики диоксида ти... more В работе изучен механизм влияния примеси марганца на электрохимические характеристики диоксида титана в модификации анатаз (Mn/Ti = 0.05; 0.1; 0.2). Установлено, что введение Mn 3+ в структуру TiO 2 приводит к образованию твердого раствора Ti 1−x Mn x O 2 и сопровождается увеличением объема элементарной ячейки с 136.41 Å 3 (недопированный образец) до 137.25 Å 3 (Mn/Ti = 0.05). Для легированного TiO 2 обнаружено повышение электропроводности приблизительно на два порядка. На электроде из Ti 0.95 Mn 0.05 O 2 зафиксирована ёмкость 186 мА•ч/г после 30 циклов заряда/разряда в режиме C/10, что выше чем для недопированного TiO 2 (87 мА•ч/г) В условиях повышенной токовой нагрузки 2С легированный диоксид титана (Mn/Ti = 0.05) сохраняет обратимую ёмкость около 121 мА•ч/г.
� Comprehensive review on progress in designing TiO 2 (B) anode of lithium-ion batteries. � Detai... more � Comprehensive review on progress in designing TiO 2 (B) anode of lithium-ion batteries. � Detailed summary of practice achievements for modified TiO 2 (B). � Overview of major factors effecting the TiO 2 (B) battery performance. � Discussion of multi-faceted approaches for guaranteed optimization of TiO 2 (B). � Perspectives of TiO 2 (B) to be future anode for next-generation lithium-ion batteries.
Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol... more Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol–gel method on carbon fibre. Physico-chemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis and Brunauer–Emmett–Teller measurements. It was confirmed that Hf 4+ substitute in the Ti 4+ sites, forming Ti 1– x Hf x O 2 ( x = 0.01; 0.03; 0.05) solid solutions with an anatase crystal structure. The Ti 1– x Hf x O 2 materials are hollow microtubes (length of 10–100 µm, outer diameter of 1–5 µm) composed of nanoparticles (average size of 15–20 nm) with a surface area of 80–90 m 2 g –1 and pore volume of 0.294–0.372 cm 3 g –1 . The effect of Hf ion incorporation on the electrochemical behaviour of anatase TiO 2 in the Li-ion battery anode was investigated by galvanostati...
Progress in Natural Science: Materials International, 2018
Zr 4+ and Fco-doped TiO 2 with the formula of Ti 0.97 Zr 0.03 O 1.98 F 0.02 was facilely synthesi... more Zr 4+ and Fco-doped TiO 2 with the formula of Ti 0.97 Zr 0.03 O 1.98 F 0.02 was facilely synthesized by a sol-gel template route. The crystal structure, morphology, composition, surface area, and conductivity were characterized by Raman spectroscopy, energy-dispersive X-ray analysis, scanning electron microscopy, Brunauer−Emmett−Teller measurements, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The results demonstrate that Zr 4+ and Fhomogeneously incorporated into TiO 2 , forming solid solution with an anatase structure. Ti 0.97 Zr 0.03 O 1.98 F 0.02 shows outstanding electrochemical properties as Li-ion battery anode in comparison with Ti 0.97 Zr 0.03 O 2. In particular, upon 35-fold cycling at 1C-rate Zr 4+ /Fco-doped TiO 2 delivers a reversible capacity of 163 mAh g-1 , whereas Zr 4+-doped TiO 2 gives only 34 mA h g-1. Additionally, Zr 4+ /Fco-doped TiO 2 retains a capacity of 138 mA h g-1 during cycling even at 10 C. The enhance performance originates from improved conductivity of Zr 4+ /Fco-doped TiO 2 material through generation of Ti 3+ (serving as electron donors) into the crystal lattice and, possibly, due to F-doping blocked the anode surface from attack of HF formed as electrolyte decomposition product.
Metallic implants have been successfully used in medicine for the past 60–70 years. Historically,... more Metallic implants have been successfully used in medicine for the past 60–70 years. Historically, implants were designed only as mechanical devices, whereas the biological aspects of their application were beyond the researchers’ interest. The improvement of living conditions and the increase of the average life span have changed the situation. The clinical requirements for medical implants rise up substantially. Presently, it seems impossible to imagine the use of metallic implants in the human body without preliminary surface modification to modulate the interaction between the surrounding biological environment and the implant. The review highlights the most recent advances in the field of functional coatings formed on implants by the plasma electrolytic oxidation technology. Special attention is dedicated to the principles of surface modification of the commercially pure titanium, titanium nickelide, and Mg-Mn-Ce magnesium alloy. The advantages and disadvantages of the method an...
A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In p... more A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In particular, the method of pulsed high-voltage discharge was adopted for synthesis of α-MoO3 nanostructure with orthorhombic crystal lattice. The as-prepared α-MoO3 was investigated as anode for Li-ion battery. The 30-fold charge–discharge cycling has shown that material specific capacity (approximately 90 mAh g–1) is not high, however excellent reversibility was achieved (the Coulombic efficiency equals to 99.9%). Thus the method opens new ways for the synthesis of nanomaterials with stable reversible capacities for Li-ion batteries.
ABSTRACT It has been demonstrated for the first time that an original method of pulsed high-volta... more ABSTRACT It has been demonstrated for the first time that an original method of pulsed high-voltage discharge is efficient for the preparing of nanostructures promising for application in Li-ion batteries. In particular, a nanostructured TiO2–TiOF2 composite is synthesized as a result of destructing Ti electrodes and polytetrafluoroethylene in plasma. It is established that TiO2–TiOF2 is a porous structure composed of TiO2 and TiOF2 nanocrystallites 40–200 nm in size. The diameter of pores varies from 3 to 5 nm. The discharge capacity of a Li/TiO2–TiOF2 half-cell during a first cycle at a current density of 20 mA/g in voltage range from 3 to 0.005 V amounted to 1370 mA h/g, which exceeds (due to the presence of TiO2) the theoretical capacity of TiOF2. The cycling of Li/TiO2–TiOF2 characterizes the stability of the capacity about 205 mA h/g after the 20th cycle.
The possibility of the use of Klason lignin extracted from sunflower husks as a cathode-active ma... more The possibility of the use of Klason lignin extracted from sunflower husks as a cathode-active material for primary lithium battery has been demonstrated for the first time. The chemical composition, morphological and physical features were characterized by X-ray energy dispersive spectroscopy, impedance spectroscopy, scanning electron microscopy, and infrared spectroscopy. Electrochemical behavior of Klason lignin vs. Li/Li + was studied by galvanostatic discharge and cyclic voltammetry. The reaction mechanism in electrochemical system was discussed. The maximum specific capacity of Klason lignin amounted to 380 mAh g-1 at a current density of 25 mA g-1 .
Journal of Industrial and Engineering Chemistry, 2014
ABSTRACT Electrochemical energy production has been extensively used in large scale applications.... more ABSTRACT Electrochemical energy production has been extensively used in large scale applications. At present, organic compounds are considered as efficient and environmentally friendly electrode materials. The paper describes the study of the possibility of using hydrolysis lignin as the lithium battery cathode material. Hydrolysis lignin features have been investigated by the impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The discharge performance of hydrolysis lignin-based lithium battery was investigated at room temperature using 1 M LiBF4 in gamma-butyrolacton electrolyte system. It was found that the specific capacity of hydrolysis lignin was equal to 450 mAh g(-1) at a discharge current density of 25 mu A/cm(2). Two main voltage plateaus located at similar to 1.8 and similar to 1.1 V were observed. The chemical composition of cathode materials upon battery discharge down to 0.9 V was studied by the X-ray photoelectron spectroscopy and infrared spectroscopy. The suggestions on possible electrochemical reactions occurring in the lithium/hydrolysis lignin system were made on the basis of the products composition analysis. The results demonstrate the potential of hydrolysis lignin based batteries to be used as low-rate power sources.
Nanocrystalline layer-structured monoclinic Na2Ti3O7 is currently under consideration for usage i... more Nanocrystalline layer-structured monoclinic Na2Ti3O7 is currently under consideration for usage in solid state electrolyte applications or electrochemical devices, including sodium-ion batteries, fuel cells, and sensors. Herein, a facile one-pot hydrothermal synthetic procedure is developed to prepare self-assembled moss-like hierarchical porous structure constructed by ultrathin Na2Ti3O7 nanotubes with an outer diameter of 6–9 nm, a wall thickness of 2–3 nm, and a length of several hundred nanometers. The phase and chemical transformations, optoelectronic, conductive, and electrochemical properties of as-prepared hierarchically-organized Na2Ti3O7 nanotubes have been studied. It is established that the obtained substance possesses an electrical conductivity of 3.34 × 10−4 S/cm at room temperature allowing faster motion of charge carriers. Besides, the unique hierarchical Na2Ti3O7 architecture exhibits promising cycling and rate performance as an anode material for sodium-ion batteri...
Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique. It was ... more Nickel- and zinc-doped TiO2(B) nanobelts were synthesized using a hydrothermal technique. It was found that the incorporation of 5 at.% Ni into bronze TiO2 expanded the unit cell by 4%. Furthermore, Ni dopant induced the 3d energy levels within TiO2(B) band structure and oxygen defects, narrowing the band gap from 3.28 eV (undoped) to 2.70 eV. Oppositely, Zn entered restrictedly into TiO2(B), but nonetheless, improves its electronic properties (Eg is narrowed to 3.21 eV). The conductivity of nickel- (2.24 × 10−8 S·cm−1) and zinc-containing (3.29 × 10−9 S·cm−1) TiO2(B) exceeds that of unmodified TiO2(B) (1.05 × 10−10 S·cm−1). When tested for electrochemical storage, nickel-doped mesoporous TiO2(B) nanobelts exhibited improved electrochemical performance. For lithium batteries, a reversible capacity of 173 mAh·g−1 was reached after 100 cycles at the current load of 50 mA·g−1, whereas, for unmodified and Zn-doped samples, around 140 and 151 mAh·g−1 was obtained. Moreover, Ni doping enh...
Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol... more Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol-gel method on carbon fiber. Physicochemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis, and Brunauer−Emmett−Teller measurements. It was confirmed that Hf4+ substitute in the Ti4+ sites, forming Ti1–xHfxO2 (x = 0.01; 0.03; 0.05) solid solutions with an anatase crystal structure. The Ti1–xHfxO2 materials are hollow microtubes (length of 10–100 μm, outer diameter of 1–5 μm) composed of nanoparticles (average size of 15–20 nm) with surface area of 80–90 m2 g–1 and pore volume of 0.294–0.372 cm3 g–1. The effect of hafnium ions incorporation on electrochemical behavior of anatase TiO2 as Li-ion battery anode was investigated by galvanostatic charge/discharge and electrochemical impedance spectroscopy. It was established that Ti0.95Hf0.05O2 shows significantly higher reversibility (154.2 mAh g–1) after 35-fold cycling at C/10 rate in comparison with undoped titania (55.9 mAh g–1). The better performance offered by Hf4+ substitution of the Ti4+ into anatase TiO2 mainly results from more open crystal structure, which has been achieved via the difference in ionic radius values of Ti4+ (0.604 Å) and Hf4+ (0.71 Å). The obtained results are in a strong accordance with ones for anatase TiO2 doped via Zr4+ (0.72 Å) published earlier. Furthermore, improved electrical conductivity of Hf-doped anatase TiO2 materials due to charge redistribution in the lattice and enhanced interfacial lithium storage due to increased surface area directly depending on Hf/Ti atomic ratio have beneficial effect on electrochemical properties
Гидротермальным синтезом получены нанотрубки диоксида титана со структурой бронз (TiO 2 (B)), доп... more Гидротермальным синтезом получены нанотрубки диоксида титана со структурой бронз (TiO 2 (B)), допированного ванадием. Синтезированный материал характеризуется мезопористостью и высокой удельной площадью поверхности, достигающей 180 м 2 /г. Показано, что введение ванадия в кристаллическую структуру TiO 2 (B) сопровождается увеличением объема элементарной ячейки. Для допированного диоксида титана по сравнению с недопированным зафиксировано повышение электропроводности приблизительно на три порядка вплоть до 1.70 • 10 −8 См/см. При использовании в качестве анодного материала литийионного аккумулятора V-замещенная производная TiO 2 (B) продемонстрировала улучшенные циклические и мощностные характеристики. В частности, после 100 циклов заряда/разряда в режиме 9С на электроде из допированного диоксида титана достигнута ёмкость 133 мА•ч/г с эффективностью циклирования более 98.9%. В условиях высокой токовой нагрузки 18С допированный TiO 2 (B) сохраняет обратимую ёмкость на уровне 114 мА•ч/г, что отвечает 40% от ёмкости первоначального разряда при 0.45C. Ключевые слова: литий-ионный аккумулятор, анод, TiO 2 (B), допирование, нанотрубки, мезопористость.
Journal of Materials Science & Technology, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
В работе изучен механизм влияния примеси марганца на электрохимические характеристики диоксида ти... more В работе изучен механизм влияния примеси марганца на электрохимические характеристики диоксида титана в модификации анатаз (Mn/Ti = 0.05; 0.1; 0.2). Установлено, что введение Mn 3+ в структуру TiO 2 приводит к образованию твердого раствора Ti 1−x Mn x O 2 и сопровождается увеличением объема элементарной ячейки с 136.41 Å 3 (недопированный образец) до 137.25 Å 3 (Mn/Ti = 0.05). Для легированного TiO 2 обнаружено повышение электропроводности приблизительно на два порядка. На электроде из Ti 0.95 Mn 0.05 O 2 зафиксирована ёмкость 186 мА•ч/г после 30 циклов заряда/разряда в режиме C/10, что выше чем для недопированного TiO 2 (87 мА•ч/г) В условиях повышенной токовой нагрузки 2С легированный диоксид титана (Mn/Ti = 0.05) сохраняет обратимую ёмкость около 121 мА•ч/г.
� Comprehensive review on progress in designing TiO 2 (B) anode of lithium-ion batteries. � Detai... more � Comprehensive review on progress in designing TiO 2 (B) anode of lithium-ion batteries. � Detailed summary of practice achievements for modified TiO 2 (B). � Overview of major factors effecting the TiO 2 (B) battery performance. � Discussion of multi-faceted approaches for guaranteed optimization of TiO 2 (B). � Perspectives of TiO 2 (B) to be future anode for next-generation lithium-ion batteries.
Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol... more Hafnium-doped titania (Hf/Ti = 0.01; 0.03; 0.05) had been facilely synthesized via a template sol–gel method on carbon fibre. Physico-chemical properties of the as-synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, scanning transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry analysis and Brunauer–Emmett–Teller measurements. It was confirmed that Hf 4+ substitute in the Ti 4+ sites, forming Ti 1– x Hf x O 2 ( x = 0.01; 0.03; 0.05) solid solutions with an anatase crystal structure. The Ti 1– x Hf x O 2 materials are hollow microtubes (length of 10–100 µm, outer diameter of 1–5 µm) composed of nanoparticles (average size of 15–20 nm) with a surface area of 80–90 m 2 g –1 and pore volume of 0.294–0.372 cm 3 g –1 . The effect of Hf ion incorporation on the electrochemical behaviour of anatase TiO 2 in the Li-ion battery anode was investigated by galvanostati...
Progress in Natural Science: Materials International, 2018
Zr 4+ and Fco-doped TiO 2 with the formula of Ti 0.97 Zr 0.03 O 1.98 F 0.02 was facilely synthesi... more Zr 4+ and Fco-doped TiO 2 with the formula of Ti 0.97 Zr 0.03 O 1.98 F 0.02 was facilely synthesized by a sol-gel template route. The crystal structure, morphology, composition, surface area, and conductivity were characterized by Raman spectroscopy, energy-dispersive X-ray analysis, scanning electron microscopy, Brunauer−Emmett−Teller measurements, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The results demonstrate that Zr 4+ and Fhomogeneously incorporated into TiO 2 , forming solid solution with an anatase structure. Ti 0.97 Zr 0.03 O 1.98 F 0.02 shows outstanding electrochemical properties as Li-ion battery anode in comparison with Ti 0.97 Zr 0.03 O 2. In particular, upon 35-fold cycling at 1C-rate Zr 4+ /Fco-doped TiO 2 delivers a reversible capacity of 163 mAh g-1 , whereas Zr 4+-doped TiO 2 gives only 34 mA h g-1. Additionally, Zr 4+ /Fco-doped TiO 2 retains a capacity of 138 mA h g-1 during cycling even at 10 C. The enhance performance originates from improved conductivity of Zr 4+ /Fco-doped TiO 2 material through generation of Ti 3+ (serving as electron donors) into the crystal lattice and, possibly, due to F-doping blocked the anode surface from attack of HF formed as electrolyte decomposition product.
Metallic implants have been successfully used in medicine for the past 60–70 years. Historically,... more Metallic implants have been successfully used in medicine for the past 60–70 years. Historically, implants were designed only as mechanical devices, whereas the biological aspects of their application were beyond the researchers’ interest. The improvement of living conditions and the increase of the average life span have changed the situation. The clinical requirements for medical implants rise up substantially. Presently, it seems impossible to imagine the use of metallic implants in the human body without preliminary surface modification to modulate the interaction between the surrounding biological environment and the implant. The review highlights the most recent advances in the field of functional coatings formed on implants by the plasma electrolytic oxidation technology. Special attention is dedicated to the principles of surface modification of the commercially pure titanium, titanium nickelide, and Mg-Mn-Ce magnesium alloy. The advantages and disadvantages of the method an...
A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In p... more A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In particular, the method of pulsed high-voltage discharge was adopted for synthesis of α-MoO3 nanostructure with orthorhombic crystal lattice. The as-prepared α-MoO3 was investigated as anode for Li-ion battery. The 30-fold charge–discharge cycling has shown that material specific capacity (approximately 90 mAh g–1) is not high, however excellent reversibility was achieved (the Coulombic efficiency equals to 99.9%). Thus the method opens new ways for the synthesis of nanomaterials with stable reversible capacities for Li-ion batteries.
ABSTRACT It has been demonstrated for the first time that an original method of pulsed high-volta... more ABSTRACT It has been demonstrated for the first time that an original method of pulsed high-voltage discharge is efficient for the preparing of nanostructures promising for application in Li-ion batteries. In particular, a nanostructured TiO2–TiOF2 composite is synthesized as a result of destructing Ti electrodes and polytetrafluoroethylene in plasma. It is established that TiO2–TiOF2 is a porous structure composed of TiO2 and TiOF2 nanocrystallites 40–200 nm in size. The diameter of pores varies from 3 to 5 nm. The discharge capacity of a Li/TiO2–TiOF2 half-cell during a first cycle at a current density of 20 mA/g in voltage range from 3 to 0.005 V amounted to 1370 mA h/g, which exceeds (due to the presence of TiO2) the theoretical capacity of TiOF2. The cycling of Li/TiO2–TiOF2 characterizes the stability of the capacity about 205 mA h/g after the 20th cycle.
The possibility of the use of Klason lignin extracted from sunflower husks as a cathode-active ma... more The possibility of the use of Klason lignin extracted from sunflower husks as a cathode-active material for primary lithium battery has been demonstrated for the first time. The chemical composition, morphological and physical features were characterized by X-ray energy dispersive spectroscopy, impedance spectroscopy, scanning electron microscopy, and infrared spectroscopy. Electrochemical behavior of Klason lignin vs. Li/Li + was studied by galvanostatic discharge and cyclic voltammetry. The reaction mechanism in electrochemical system was discussed. The maximum specific capacity of Klason lignin amounted to 380 mAh g-1 at a current density of 25 mA g-1 .
Journal of Industrial and Engineering Chemistry, 2014
ABSTRACT Electrochemical energy production has been extensively used in large scale applications.... more ABSTRACT Electrochemical energy production has been extensively used in large scale applications. At present, organic compounds are considered as efficient and environmentally friendly electrode materials. The paper describes the study of the possibility of using hydrolysis lignin as the lithium battery cathode material. Hydrolysis lignin features have been investigated by the impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The discharge performance of hydrolysis lignin-based lithium battery was investigated at room temperature using 1 M LiBF4 in gamma-butyrolacton electrolyte system. It was found that the specific capacity of hydrolysis lignin was equal to 450 mAh g(-1) at a discharge current density of 25 mu A/cm(2). Two main voltage plateaus located at similar to 1.8 and similar to 1.1 V were observed. The chemical composition of cathode materials upon battery discharge down to 0.9 V was studied by the X-ray photoelectron spectroscopy and infrared spectroscopy. The suggestions on possible electrochemical reactions occurring in the lithium/hydrolysis lignin system were made on the basis of the products composition analysis. The results demonstrate the potential of hydrolysis lignin based batteries to be used as low-rate power sources.
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Papers by Denis Opra