Jianming Bai - Academia.edu (original) (raw)
Papers by Jianming Bai
![Research paper thumbnail of {"__content__"=>"Author Correction: NaAlTiO, A Novel Anode Material for Sodium Ion Battery.", "sub"=>[{"__content__"=>"3"}, {"__content__"=>"8"}]}](https://attachments.academia-assets.com/104020544/thumbnails/1.jpg)
](Scientific reports, 2018
A correction to this article has been published and is linked from the HTML version of this paper... more A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
The Journal of Physical Chemistry C, 2010
The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga1− x Zn x)(N1− x O... more The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga1− x Zn x)(N1− x O x) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path,(Ga1− ...
Journal of Physics D: Applied Physics, 2005
APS Meeting Abstracts, Mar 1, 2001
An exploration of correlations between local and long-range periodic structure in a colossal magn... more An exploration of correlations between local and long-range periodic structure in a colossal magnetoresistance (CMR) manganite bulk specimen has been carried out. High-quality polycrystalline samples of CMR perovskite La_0. 6Y_0. 07Ca_0. 33MnO 3 (LYCMO) have been prepared by solid-state synthesis of precursor oxides and carbonates. High-resolution synchotron x-ray diffraction (XRD) data was collected and Rietveld refinement of long-range periodic structure was performed. Local structural characterization about Mn, Y ...
The Journal of Physical Chemistry Letters, 2019
Chemistry of Materials, 2019
Science Advances, 2020
In chemical reactions, the breaking and formation of chemical bonds usually need external energy ... more In chemical reactions, the breaking and formation of chemical bonds usually need external energy to overcome the activation barriers. Conventional energy delivery transfers energy from heating sources via various media, hence losing efficiency and inducing side reactions. In contrast, microwave (MW) heating is known to be highly energy efficient through dipole interaction with polar media, but how exactly it transmits energy to initiate chemical reactions has been unknown. Here, we report a rigorous determination of energy delivery mechanisms underlying MW-enabled rapid hydrothermal synthesis, by monitoring the structure and temperature of all the involved components as solid-liquid intercalation reaction occurs using in situ synchrotron techniques. We reveal a hitherto unknown direct energy transmission between MW irradiation source and the targeted reactants, leading to greatly reduced energy waste, and so the ultrafast kinetics at low temperature. These findings open up new horiz...
Journal of the American Chemical Society, 2019
Journal of Materials Chemistry A, 2018
Nickel-rich layered transition metal oxides (NMCs) have been intensively studied as promising cat... more Nickel-rich layered transition metal oxides (NMCs) have been intensively studied as promising cathode candidates for next-generation Li-ion batteries, known for low cost and high theoretical capacity. However, the practical capacity...
Journal of the American Chemical Society, Jan 3, 2018
Metal (M) oxides are one of the most interesting and widely used solids, and many of their proper... more Metal (M) oxides are one of the most interesting and widely used solids, and many of their properties can be directly correlated to the local structural ordering within basic building units (BBUs). One particular example is the high-Ni transition metal layered oxides, potential cathode materials for Li-ion batteries whose electrochemical activity is largely determined by the cationic ordering in octahedra (e.g., the BBUs in such systems). Yet to be firmly established is how the BBUs are inherited from precursors and subsequently evolve into the desired ordering during synthesis. Herein, a multimodal in situ X-ray characterization approach is employed to investigate the synthesis process in preparing LiNiMnCoO from its hydroxide counterpart, at scales varying from the long-range to local individual octahedral units. Real-time observation corroborated by first-principles calculations reveals a topotactic transformation throughout the entire process, during which the layered framework ...
Energy Storage Materials, 2018
Inorganic Chemistry, 2018
TiF exhibits a rhombohedral to ReO-type cubic phase transformation at ∼340 K. Here we report that... more TiF exhibits a rhombohedral to ReO-type cubic phase transformation at ∼340 K. Here we report that, by introducing ZrF into TiF, the cubic phase is stabilized at least down to 123 K in the TiZr F compounds. All compounds exhibit low thermal expansion (LTE) between 123 and 623 K, and a nearly zero thermal expansion (ZTE) was obtained in TiZrF (α = 0.91 ppm/K). The analysis of pair distribution function reveals that the cation-centered octahedra are partially changed to pentagonal bipyramids in TiZr F due to the excess fluorines relative to the case of TiF. Therefore, the cooperative rotation of the polyhedra tends to be restricted, and the cubic phase is thus stabilized. The restrained polyhedral rotations compete against the lattice softening caused by the introduction of Zr, giving rise to the LTE. Our present strategy is applicable to other rhombohedral metal trifluorides for the design of new isotropic ZTE materials.
Scientific reports, Jan 11, 2017
Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-... more Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode's electrical conductivity to improve the battery's power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte. Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we em...
Journal of the American Chemical Society, 2017
Motivated by predictions made using a bond valence sum difference map (BVS-DM) analysis, the nove... more Motivated by predictions made using a bond valence sum difference map (BVS-DM) analysis, the novel Li-ion conductor Li2Mg2P3O9N was synthesized by ion exchange from a Na2Mg2P3O9N precursor. Impedance spectroscopy measurements indicate that Li2Mg2P3O9N has a room temperature Li-ion conductivity of about 10(-6) S/cm (comparable to LiPON), which is 6 orders of magnitude higher than the extrapolated Na-ion conductivity of Na2Mg2P3O9N at this temperature. The structure of Li2Mg2P3O9N was determined from ex situ synchrotron and time-of-flight neutron diffraction data to retain the P213 space group, though with a cubic lattice parameter of a = 9.11176(8) Å that is significantly smaller than the a = 9.2439(1) Å of Na2Mg2P3O9N. The two Li-ion sites are found to be very substantially displaced (∼0.5 Å) relative to the analogous Na sites in the precursor phase. The non-molten salt ion exchange method used to prepare Li2Mg2P3O9N produces a minimal background in powder diffraction experiments, and was therefore exploited for the first time to follow a Li(+)/Na(+) ion exchange reaction using in situ powder neutron diffraction. Lattice parameter changes during ion exchange suggest that the reaction proceeds through a Na2-xLixMg2P3O9N solid solution (stage 1) followed by a two-phase reaction (stage 2) to form Li2Mg2P3O9N. However, full Rietveld refinements of the in situ neutron diffraction data indicate that the actual transformation mechanism is more complex and instead involves two thermodynamically distinct solid solutions in which the Li exclusively occupies the Li1 site at low Li contents (stage 1a) and then migrates to the Li3 site at higher Li contents (stage 1b), a crossover driven by the different signs of the local volume change at these sites. In addition to highlighting the importance of obtaining full structural data in situ throughout the ion exchange process, these results provide insights into the general question of what constitutes a thermodynamic phase.
Advanced materials (Deerfield Beach, Fla.), Jan 25, 2017
Nickel-rich layered transition metal oxides, LiNi1-x (MnCo)x O2 (1-x ≥ 0.5), are appealing candid... more Nickel-rich layered transition metal oxides, LiNi1-x (MnCo)x O2 (1-x ≥ 0.5), are appealing candidates for cathodes in next-generation lithium-ion batteries (LIBs) for electric vehicles and other large-scale applications, due to their high capacity and low cost. However, synthetic control of the structural ordering in such a complex quaternary system has been a great challenge, especially in the presence of high Ni content. Herein, synthesis reactions for preparing layered LiNi0.7 Mn0.15 Co0.15 O2 (NMC71515) by solid-state methods are investigated through a combination of time-resolved in situ high-energy X-ray diffraction and absorption spectroscopy measurements. The real-time observation reveals a strong temperature dependence of the kinetics of cationic ordering in NMC71515 as a result of thermal-driven oxidation of transition metals and lithium/oxygen loss that concomitantly occur during heat treatment. Through synthetic control of the kinetic reaction pathway, a layered NMC71515...
Advanced Energy Materials, 2016
Scientific reports, 2018
A correction to this article has been published and is linked from the HTML version of this paper... more A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
The Journal of Physical Chemistry C, 2010
The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga1− x Zn x)(N1− x O... more The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga1− x Zn x)(N1− x O x) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path,(Ga1− ...
Journal of Physics D: Applied Physics, 2005
APS Meeting Abstracts, Mar 1, 2001
An exploration of correlations between local and long-range periodic structure in a colossal magn... more An exploration of correlations between local and long-range periodic structure in a colossal magnetoresistance (CMR) manganite bulk specimen has been carried out. High-quality polycrystalline samples of CMR perovskite La_0. 6Y_0. 07Ca_0. 33MnO 3 (LYCMO) have been prepared by solid-state synthesis of precursor oxides and carbonates. High-resolution synchotron x-ray diffraction (XRD) data was collected and Rietveld refinement of long-range periodic structure was performed. Local structural characterization about Mn, Y ...
The Journal of Physical Chemistry Letters, 2019
Chemistry of Materials, 2019
Science Advances, 2020
In chemical reactions, the breaking and formation of chemical bonds usually need external energy ... more In chemical reactions, the breaking and formation of chemical bonds usually need external energy to overcome the activation barriers. Conventional energy delivery transfers energy from heating sources via various media, hence losing efficiency and inducing side reactions. In contrast, microwave (MW) heating is known to be highly energy efficient through dipole interaction with polar media, but how exactly it transmits energy to initiate chemical reactions has been unknown. Here, we report a rigorous determination of energy delivery mechanisms underlying MW-enabled rapid hydrothermal synthesis, by monitoring the structure and temperature of all the involved components as solid-liquid intercalation reaction occurs using in situ synchrotron techniques. We reveal a hitherto unknown direct energy transmission between MW irradiation source and the targeted reactants, leading to greatly reduced energy waste, and so the ultrafast kinetics at low temperature. These findings open up new horiz...
Journal of the American Chemical Society, 2019
Journal of Materials Chemistry A, 2018
Nickel-rich layered transition metal oxides (NMCs) have been intensively studied as promising cat... more Nickel-rich layered transition metal oxides (NMCs) have been intensively studied as promising cathode candidates for next-generation Li-ion batteries, known for low cost and high theoretical capacity. However, the practical capacity...
Journal of the American Chemical Society, Jan 3, 2018
Metal (M) oxides are one of the most interesting and widely used solids, and many of their proper... more Metal (M) oxides are one of the most interesting and widely used solids, and many of their properties can be directly correlated to the local structural ordering within basic building units (BBUs). One particular example is the high-Ni transition metal layered oxides, potential cathode materials for Li-ion batteries whose electrochemical activity is largely determined by the cationic ordering in octahedra (e.g., the BBUs in such systems). Yet to be firmly established is how the BBUs are inherited from precursors and subsequently evolve into the desired ordering during synthesis. Herein, a multimodal in situ X-ray characterization approach is employed to investigate the synthesis process in preparing LiNiMnCoO from its hydroxide counterpart, at scales varying from the long-range to local individual octahedral units. Real-time observation corroborated by first-principles calculations reveals a topotactic transformation throughout the entire process, during which the layered framework ...
Energy Storage Materials, 2018
Inorganic Chemistry, 2018
TiF exhibits a rhombohedral to ReO-type cubic phase transformation at ∼340 K. Here we report that... more TiF exhibits a rhombohedral to ReO-type cubic phase transformation at ∼340 K. Here we report that, by introducing ZrF into TiF, the cubic phase is stabilized at least down to 123 K in the TiZr F compounds. All compounds exhibit low thermal expansion (LTE) between 123 and 623 K, and a nearly zero thermal expansion (ZTE) was obtained in TiZrF (α = 0.91 ppm/K). The analysis of pair distribution function reveals that the cation-centered octahedra are partially changed to pentagonal bipyramids in TiZr F due to the excess fluorines relative to the case of TiF. Therefore, the cooperative rotation of the polyhedra tends to be restricted, and the cubic phase is thus stabilized. The restrained polyhedral rotations compete against the lattice softening caused by the introduction of Zr, giving rise to the LTE. Our present strategy is applicable to other rhombohedral metal trifluorides for the design of new isotropic ZTE materials.
Scientific reports, Jan 11, 2017
Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-... more Conductive metal sulfides are promising multi-functional additives for future lithium-sulfur (Li-S) batteries. These can increase the sulfur cathode's electrical conductivity to improve the battery's power capability, as well as contribute to the overall cell-discharge capacity. This multi-functional electrode design showed initial promise; however, complicated interactions at the system level are accompanied by some detrimental side effects. The metal sulfide additives with a chemical conversion as the reaction mechanism, e.g., CuS and FeS, can increase the theoretical capacity of the Li-S system. However, these additives may cause undesired parasitic reactions, such as the dissolution of the additive in the electrolyte. Studying such complex reactions presents a challenge because it requires experimental methods that can track the chemical and structural evolution of the system during an electrochemical process. To address the fundamental mechanisms in these systems, we em...
Journal of the American Chemical Society, 2017
Motivated by predictions made using a bond valence sum difference map (BVS-DM) analysis, the nove... more Motivated by predictions made using a bond valence sum difference map (BVS-DM) analysis, the novel Li-ion conductor Li2Mg2P3O9N was synthesized by ion exchange from a Na2Mg2P3O9N precursor. Impedance spectroscopy measurements indicate that Li2Mg2P3O9N has a room temperature Li-ion conductivity of about 10(-6) S/cm (comparable to LiPON), which is 6 orders of magnitude higher than the extrapolated Na-ion conductivity of Na2Mg2P3O9N at this temperature. The structure of Li2Mg2P3O9N was determined from ex situ synchrotron and time-of-flight neutron diffraction data to retain the P213 space group, though with a cubic lattice parameter of a = 9.11176(8) Å that is significantly smaller than the a = 9.2439(1) Å of Na2Mg2P3O9N. The two Li-ion sites are found to be very substantially displaced (∼0.5 Å) relative to the analogous Na sites in the precursor phase. The non-molten salt ion exchange method used to prepare Li2Mg2P3O9N produces a minimal background in powder diffraction experiments, and was therefore exploited for the first time to follow a Li(+)/Na(+) ion exchange reaction using in situ powder neutron diffraction. Lattice parameter changes during ion exchange suggest that the reaction proceeds through a Na2-xLixMg2P3O9N solid solution (stage 1) followed by a two-phase reaction (stage 2) to form Li2Mg2P3O9N. However, full Rietveld refinements of the in situ neutron diffraction data indicate that the actual transformation mechanism is more complex and instead involves two thermodynamically distinct solid solutions in which the Li exclusively occupies the Li1 site at low Li contents (stage 1a) and then migrates to the Li3 site at higher Li contents (stage 1b), a crossover driven by the different signs of the local volume change at these sites. In addition to highlighting the importance of obtaining full structural data in situ throughout the ion exchange process, these results provide insights into the general question of what constitutes a thermodynamic phase.
Advanced materials (Deerfield Beach, Fla.), Jan 25, 2017
Nickel-rich layered transition metal oxides, LiNi1-x (MnCo)x O2 (1-x ≥ 0.5), are appealing candid... more Nickel-rich layered transition metal oxides, LiNi1-x (MnCo)x O2 (1-x ≥ 0.5), are appealing candidates for cathodes in next-generation lithium-ion batteries (LIBs) for electric vehicles and other large-scale applications, due to their high capacity and low cost. However, synthetic control of the structural ordering in such a complex quaternary system has been a great challenge, especially in the presence of high Ni content. Herein, synthesis reactions for preparing layered LiNi0.7 Mn0.15 Co0.15 O2 (NMC71515) by solid-state methods are investigated through a combination of time-resolved in situ high-energy X-ray diffraction and absorption spectroscopy measurements. The real-time observation reveals a strong temperature dependence of the kinetics of cationic ordering in NMC71515 as a result of thermal-driven oxidation of transition metals and lithium/oxygen loss that concomitantly occur during heat treatment. Through synthetic control of the kinetic reaction pathway, a layered NMC71515...
Advanced Energy Materials, 2016