Dongli Zeng | SUNY: Stony Brook University (original) (raw)
Papers by Dongli Zeng
Chemistry of Materials, May 24, 2021
The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 h... more The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 has been investigated by using a combination of in situ powder X-ray diffraction and ex situ neutron powder diffraction, X-ray absorption and 7 Li NMR spectroscopy, together with a range of electrochemical experiments. Sr 2 MnO 2 Cu 4−δ S 3 consists of [Sr 2 MnO 2 ] perovskite-type cationic layers alternating with highly defective antifluorite-type [Cu 4−δ S 3 ] (δ ≈ 0.5) anionic layers. It undergoes a combined displacement/intercalation (CDI) mechanism on reaction with Li, where the inserted Li replaces Cu, forming Li 4 S 3 slabs and Cu + is reduced and extruded as metallic particles. For the initial 2−3% of the first discharge process, the vacant sites in the sulfide layer are filled by Li; Cu extrusion then accompanies further insertion of Li. Mn 2.5+ is reduced to Mn 2+ during the first half of the discharge. The overall charging process involves the removal of Li and re-insertion of Cu into the sulfide layers with re-oxidation of Mn 2+ to Mn 2.5+. However, due to the different diffusivities of Li and Cu, the processes operating on charge are quite different from those operating during the first discharge: charging to 2.75 V results in the removal of most of the Li, little reinsertion of Cu, and good capacity retention. A charge to 3.75 V is required to fully reinsert Cu, which results in significant changes to the sulfide sublattice during the following discharge and poor capacity retention. This detailed structure−property investigation will promote the design of new functional electrodes with improved device performance.
The Electrochemical Society interface, 2011
![Research paper thumbnail of Cation Ordering in Li[Ni<sub><i>x</i></sub>Mn<sub><i>x</i></sub>Co<sub>(1–2<i>x</i>)</sub>]O<sub>2</sub>-Layered Cathode Materials: A Nuclear Magnetic Resonance (NMR), Pair Distribution Function, X-ray Absorption Spectroscopy, and Electrochemical Study](https://attachments.academia-assets.com/109610898/thumbnails/1.jpg)
](Chemistry of Materials, Nov 15, 2007
Meeting abstracts, 2010
not Available.
MRS Proceedings, 2006
The layered oxysulfides Sr2MO2Cu2S2 (M = Mn, Co, Ni) consist of alternating perovskite-type Sr2MO... more The layered oxysulfides Sr2MO2Cu2S2 (M = Mn, Co, Ni) consist of alternating perovskite-type Sr2MO2 layers and copper sulfide layers. We studied the electrochemical insertion of Li into these three samples. By this we were able to study the influence of the nature of the transition metal on the Li insertion process which appears to be at least partially reversible. While the Mn compound clearly shows a Cu-Li exchange reaction, the electrochemical process for the two other compounds is more complex. The lithiated materials were studied by 7Li MAS NMR.
Chemistry of Materials, Aug 3, 2012
A study of the correlations between the stoichiometry, secondary phases and transition metal orde... more A study of the correlations between the stoichiometry, secondary phases and transition metal ordering of LiNi 0.5 Mn 1.5 O 4 was undertaken by characterizing samples synthesized at different temperatures. Insight into the composition of the samples was obtained by electron microscopy, neutron diffraction and X-ray absorption spectroscopy. In turn, analysis of cationic ordering was performed by combining neutron diffraction with Li MAS NMR spectroscopy. Under the conditions chosen for the synthesis, all samples systematically showed an excess of Mn, which was compensated by the formation of a secondary rock salt phase and not via the creation of oxygen vacancies. Local deviations from the ideal 3:1 Mn:Ni ordering were found, even for samples that show the superlattice ordering by diffraction, with different disordered schemes also being possible. The magnetic behavior of the samples was correlated with the deviations from this ideal ordering arrangement. The in-depth crystal-chemical knowledge generated was employed to evaluate the influence of these parameters on the electrochemical behavior of the materials.
Meeting abstracts, 2011
not Available.
![Research paper thumbnail of Investigation of the Structural Changes in Li[Ni<sub><i>y</i></sub>Mn<sub><i>y</i></sub>Co<sub>(1−2<i>y</i>)</sub>]O<sub>2</sub> (<i>y</i> = 0.05) upon Electrochemical Lithium Deintercalation](https://attachments.academia-assets.com/109610892/thumbnails/1.jpg)
](Chemistry of Materials, Jan 4, 2010
Solid State Ionics, Jul 26, 2010
The electrochemical behavior of chemically modified tunneltype Ba 6 Mn 24 O 48 powder and whisker... more The electrochemical behavior of chemically modified tunneltype Ba 6 Mn 24 O 48 powder and whiskers has been examined in terms of the lithium intercalation/deintercalation. A maximum overall specific capacity of 136 mAh/g was achieved for the nanostructured form of the proton-exchanged Ba 6 Mn 24 O 48 phase. This phase is formed by Ba 2+ /H + exchange, a process which is also accompanied by Mn dissolution, a commensurate increase in the Mn oxidation state, and an anisotropic shrinkage of the unit cell. Three types of lithium ions were detected in the Li NMR spectra of the chemically and electrochemically lithiated materials. Li resonances at ∼ 380 and 280 ppm, due to sites nearby both Mn 3+ /Mn 4+ ions in the large tunnels were seen in the ion-exchanged samples, while resonances at similar locations and at ∼ 100 ppm (due to Li near Mn 3+), were observed in the electrochemically lithiated materials. The investigated materials show potential as "electrochemically-active-and-reinforcing" components, and open up strategy with which to produce composite flexible electrodes for lithium-ion batteries.
Journal of Materials Chemistry, 2012
ABSTRACT
ECS Meeting Abstracts, 2008
not Available.
The Journal of Physical Chemistry C, 2015
The growth of lithium microstructures during battery cycling has, to date, prohibited the use of ... more The growth of lithium microstructures during battery cycling has, to date, prohibited the use of Li metal anodes and raises serious safety concerns even in conventional lithium-ion rechargeable batteries, particularly if they are charged at high rates. The electrochemical conditions under which these Li microstructures grow have, therefore, been investigated by in situ nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and susceptibility calculations. Lithium metal symmetric bag cells containing LiPF 6 in EC: DMC electrolytes were used. Distinct 7 Li NMR resonances were observed due to the Li metal bulk electrodes and microstructures, the changes in peak positions and intensities being monitored in situ during Li deposition. The changes in the NMR spectra, observed as a function of separator thickness and porosity (using Celgard and Whatmann glass microfiber membranes) and different applied pressures, were correlated with changes in the type of microstructure, by using SEM. Isotopically enriched 6 Li metal electrodes were used against natural abundance predominantly 7 Li metal counter electrodes to investigate radiofrequency (rf) field penetration into the Li anode and to confirm the assignment of the higher frequency peak to Li dendrites. The conclusions were supported by calculations performed to explore the effect of the different microstructures on peak position/broadening, the study showing that Li NMR spectroscopy can be used as a sensitive probe of the both the amount and type of microstructure formation.
The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 h... more The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 has been investigated by using a combination of in situ powder X-ray diffraction and ex situ neutron powder diffraction, X-ray absorption and 7 Li NMR spectroscopy, together with a range of electrochemical experiments. Sr 2 MnO 2 Cu 4−δ S 3 consists of [Sr 2 MnO 2 ] perovskite-type cationic layers alternating with highly defective antifluorite-type [Cu 4−δ S 3 ] (δ ≈ 0.5) anionic layers. It undergoes a combined displacement/intercalation (CDI) mechanism on reaction with Li, where the inserted Li replaces Cu, forming Li 4 S 3 slabs and Cu + is reduced and extruded as metallic particles. For the initial 2−3% of the first discharge process, the vacant sites in the sulfide layer are filled by Li; Cu extrusion then accompanies further insertion of Li. Mn 2.5+ is reduced to Mn 2+ during the first half of the discharge. The overall charging process involves the removal of Li and re-insertion of Cu into the sulfide layers with re-oxidation of Mn 2+ to Mn 2.5+. However, due to the different diffusivities of Li and Cu, the processes operating on charge are quite different from those operating during the first discharge: charging to 2.75 V results in the removal of most of the Li, little reinsertion of Cu, and good capacity retention. A charge to 3.75 V is required to fully reinsert Cu, which results in significant changes to the sulfide sublattice during the following discharge and poor capacity retention. This detailed structure−property investigation will promote the design of new functional electrodes with improved device performance.
Advanced characterization techniques such as synchrotron X-ray and neutron diffraction, and solid... more Advanced characterization techniques such as synchrotron X-ray and neutron diffraction, and solid state NMR, have been widely used to study lithium (de)intercalation mechanisms of novel compounds. However, the spatial distribution of the anode/cathode material has scarcely been investigated up to now. Information on a micro-scale is of substantial importance, for example, how the chemical speciation and oxidation state of the metal ion are distributed as function of location in the electrode film during the electrochemical reaction.
Chemistry of Materials, May 24, 2021
The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 h... more The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 has been investigated by using a combination of in situ powder X-ray diffraction and ex situ neutron powder diffraction, X-ray absorption and 7 Li NMR spectroscopy, together with a range of electrochemical experiments. Sr 2 MnO 2 Cu 4−δ S 3 consists of [Sr 2 MnO 2 ] perovskite-type cationic layers alternating with highly defective antifluorite-type [Cu 4−δ S 3 ] (δ ≈ 0.5) anionic layers. It undergoes a combined displacement/intercalation (CDI) mechanism on reaction with Li, where the inserted Li replaces Cu, forming Li 4 S 3 slabs and Cu + is reduced and extruded as metallic particles. For the initial 2−3% of the first discharge process, the vacant sites in the sulfide layer are filled by Li; Cu extrusion then accompanies further insertion of Li. Mn 2.5+ is reduced to Mn 2+ during the first half of the discharge. The overall charging process involves the removal of Li and re-insertion of Cu into the sulfide layers with re-oxidation of Mn 2+ to Mn 2.5+. However, due to the different diffusivities of Li and Cu, the processes operating on charge are quite different from those operating during the first discharge: charging to 2.75 V results in the removal of most of the Li, little reinsertion of Cu, and good capacity retention. A charge to 3.75 V is required to fully reinsert Cu, which results in significant changes to the sulfide sublattice during the following discharge and poor capacity retention. This detailed structure−property investigation will promote the design of new functional electrodes with improved device performance.
The Electrochemical Society interface, 2011
Chemistry of Materials, Nov 15, 2007
Meeting abstracts, 2010
not Available.
MRS Proceedings, 2006
The layered oxysulfides Sr2MO2Cu2S2 (M = Mn, Co, Ni) consist of alternating perovskite-type Sr2MO... more The layered oxysulfides Sr2MO2Cu2S2 (M = Mn, Co, Ni) consist of alternating perovskite-type Sr2MO2 layers and copper sulfide layers. We studied the electrochemical insertion of Li into these three samples. By this we were able to study the influence of the nature of the transition metal on the Li insertion process which appears to be at least partially reversible. While the Mn compound clearly shows a Cu-Li exchange reaction, the electrochemical process for the two other compounds is more complex. The lithiated materials were studied by 7Li MAS NMR.
Chemistry of Materials, Aug 3, 2012
A study of the correlations between the stoichiometry, secondary phases and transition metal orde... more A study of the correlations between the stoichiometry, secondary phases and transition metal ordering of LiNi 0.5 Mn 1.5 O 4 was undertaken by characterizing samples synthesized at different temperatures. Insight into the composition of the samples was obtained by electron microscopy, neutron diffraction and X-ray absorption spectroscopy. In turn, analysis of cationic ordering was performed by combining neutron diffraction with Li MAS NMR spectroscopy. Under the conditions chosen for the synthesis, all samples systematically showed an excess of Mn, which was compensated by the formation of a secondary rock salt phase and not via the creation of oxygen vacancies. Local deviations from the ideal 3:1 Mn:Ni ordering were found, even for samples that show the superlattice ordering by diffraction, with different disordered schemes also being possible. The magnetic behavior of the samples was correlated with the deviations from this ideal ordering arrangement. The in-depth crystal-chemical knowledge generated was employed to evaluate the influence of these parameters on the electrochemical behavior of the materials.
Meeting abstracts, 2011
not Available.
Chemistry of Materials, Jan 4, 2010
Solid State Ionics, Jul 26, 2010
The electrochemical behavior of chemically modified tunneltype Ba 6 Mn 24 O 48 powder and whisker... more The electrochemical behavior of chemically modified tunneltype Ba 6 Mn 24 O 48 powder and whiskers has been examined in terms of the lithium intercalation/deintercalation. A maximum overall specific capacity of 136 mAh/g was achieved for the nanostructured form of the proton-exchanged Ba 6 Mn 24 O 48 phase. This phase is formed by Ba 2+ /H + exchange, a process which is also accompanied by Mn dissolution, a commensurate increase in the Mn oxidation state, and an anisotropic shrinkage of the unit cell. Three types of lithium ions were detected in the Li NMR spectra of the chemically and electrochemically lithiated materials. Li resonances at ∼ 380 and 280 ppm, due to sites nearby both Mn 3+ /Mn 4+ ions in the large tunnels were seen in the ion-exchanged samples, while resonances at similar locations and at ∼ 100 ppm (due to Li near Mn 3+), were observed in the electrochemically lithiated materials. The investigated materials show potential as "electrochemically-active-and-reinforcing" components, and open up strategy with which to produce composite flexible electrodes for lithium-ion batteries.
Journal of Materials Chemistry, 2012
ABSTRACT
ECS Meeting Abstracts, 2008
not Available.
The Journal of Physical Chemistry C, 2015
The growth of lithium microstructures during battery cycling has, to date, prohibited the use of ... more The growth of lithium microstructures during battery cycling has, to date, prohibited the use of Li metal anodes and raises serious safety concerns even in conventional lithium-ion rechargeable batteries, particularly if they are charged at high rates. The electrochemical conditions under which these Li microstructures grow have, therefore, been investigated by in situ nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and susceptibility calculations. Lithium metal symmetric bag cells containing LiPF 6 in EC: DMC electrolytes were used. Distinct 7 Li NMR resonances were observed due to the Li metal bulk electrodes and microstructures, the changes in peak positions and intensities being monitored in situ during Li deposition. The changes in the NMR spectra, observed as a function of separator thickness and porosity (using Celgard and Whatmann glass microfiber membranes) and different applied pressures, were correlated with changes in the type of microstructure, by using SEM. Isotopically enriched 6 Li metal electrodes were used against natural abundance predominantly 7 Li metal counter electrodes to investigate radiofrequency (rf) field penetration into the Li anode and to confirm the assignment of the higher frequency peak to Li dendrites. The conclusions were supported by calculations performed to explore the effect of the different microstructures on peak position/broadening, the study showing that Li NMR spectroscopy can be used as a sensitive probe of the both the amount and type of microstructure formation.
The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 h... more The electrochemical lithiation and delithiation of the layered oxysulfide Sr 2 MnO 2 Cu 4−δ S 3 has been investigated by using a combination of in situ powder X-ray diffraction and ex situ neutron powder diffraction, X-ray absorption and 7 Li NMR spectroscopy, together with a range of electrochemical experiments. Sr 2 MnO 2 Cu 4−δ S 3 consists of [Sr 2 MnO 2 ] perovskite-type cationic layers alternating with highly defective antifluorite-type [Cu 4−δ S 3 ] (δ ≈ 0.5) anionic layers. It undergoes a combined displacement/intercalation (CDI) mechanism on reaction with Li, where the inserted Li replaces Cu, forming Li 4 S 3 slabs and Cu + is reduced and extruded as metallic particles. For the initial 2−3% of the first discharge process, the vacant sites in the sulfide layer are filled by Li; Cu extrusion then accompanies further insertion of Li. Mn 2.5+ is reduced to Mn 2+ during the first half of the discharge. The overall charging process involves the removal of Li and re-insertion of Cu into the sulfide layers with re-oxidation of Mn 2+ to Mn 2.5+. However, due to the different diffusivities of Li and Cu, the processes operating on charge are quite different from those operating during the first discharge: charging to 2.75 V results in the removal of most of the Li, little reinsertion of Cu, and good capacity retention. A charge to 3.75 V is required to fully reinsert Cu, which results in significant changes to the sulfide sublattice during the following discharge and poor capacity retention. This detailed structure−property investigation will promote the design of new functional electrodes with improved device performance.
Advanced characterization techniques such as synchrotron X-ray and neutron diffraction, and solid... more Advanced characterization techniques such as synchrotron X-ray and neutron diffraction, and solid state NMR, have been widely used to study lithium (de)intercalation mechanisms of novel compounds. However, the spatial distribution of the anode/cathode material has scarcely been investigated up to now. Information on a micro-scale is of substantial importance, for example, how the chemical speciation and oxidation state of the metal ion are distributed as function of location in the electrode film during the electrochemical reaction.