{"id":{"repo_id":"colo-mines","oai_identifier":"oai:repository.mines.edu:11124/172807"},"canonical_url":"https://search.dev.ndltd.org/etd/colo-mines/oai:repository.mines.edu:11124/172807","repository":{"repo_id":"colo-mines","name":"Colorado School of Mines","base_url":"https://repository.mines.edu/server/oai/request"},"display":{"title":"Redox cycles with doped calcium manganites for high-temperature thermochemical energy storage in concentrating solar power","abstract":"Redox cycles with reducible perovskite oxides of the form ABO$_3$ can provide thermochemical energy storage (TCES) with higher energy density and storage temperatures than molten-salt systems for large-scale energy storage in concentrating solar power (CSP). Perovskites from earth abundant cations are desirable for cost-effective solutions, but such materials must demonstrate appropriate thermodynamics for high specific TCES and favorable kinetics for heat-driven reduction and exothermic re-oxidation. This dissertation explores the thermodynamics and kinetics of doped CaMnO$_{3-\\delta}$ particles for TCES redox cycles where particles are heated and reduced in N$_2$ ($P_{\\text{O2}} \\approx 10^{-4}$ bar) to high temperatures (700 to $1000^{\\circ}$C) in a solid-particle solar receiver. Chemical and sensible energy stored in the reduced perovskite particles is released as needed to a supercritical CO$_2$ power cycle via re-oxidation and cooling of the material. Thermodynamics of Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ ($x=0.05$ and $0.1$) and CaCr$_y$Mn$_{1-y}$O$_{3-\\delta}$ ($y=0.05$ and $0.1$) are characterized through thermogravimetric analysis and calorimetry. Results indicate Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ compositions can store over 200 kJ kg$^{-1}$ more specific energy storage compared to inert particulate TES media for $T \\ge 900^\\circ$C; the specific energy storage potential of Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$ at $T=900^\\circ$C and $P_\\text{O2}=10^{-4}$ bar is 706 kJ kg$^{-1}$. Challenges are expected achieving these high values of energy storage in a transport-limited receiver with low residence time for CSP. Redox kinetics are explored in a packed bed reactor with rapid heating capabilities. Results in isothermal tests show that oxidation is significantly faster than reduction. Modeling of packed bed experiments indicate that reduction at $T \\ge 800^\\circ$C is limited by build-up of oxygen in the gas phase and equilibrium thermodynamics between the solid and gas phases. Long-term redox cycling tests, which simulate a nominal TCES cycle, demonstrate excellent chemical stability for all materials. A standard deviation of 1.9\\% on the extent of reduction over 1000 cycles was observed for Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$. Modeling efforts of the packed bed experiments allow for characterization of redox kinetics, to be implemented in computational models for system component design. One of the most promising compositions, Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$, is implemented in a 1-D receiver model to explore designs and operating conditions for perovskite-based energy storage systems.","abstract_html":"Redox cycles with reducible perovskite oxides of the form ABO<span class=\"etd-inline-math\"><sub>3</sub></span> can provide thermochemical energy storage (TCES) with higher energy density and storage temperatures than molten-salt systems for large-scale energy storage in concentrating solar power (CSP). Perovskites from earth abundant cations are desirable for cost-effective solutions, but such materials must demonstrate appropriate thermodynamics for high specific TCES and favorable kinetics for heat-driven reduction and exothermic re-oxidation. This dissertation explores the thermodynamics and kinetics of doped CaMnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span> particles for TCES redox cycles where particles are heated and reduced in N<span class=\"etd-inline-math\"><sub>2</sub></span> (<span class=\"etd-inline-math\">P<sub>\\text{O2}</sub> \\approx 10<sup>-4</sup></span> bar) to high temperatures (700 to <span class=\"etd-inline-math\">1000<sup>\\circ</sup></span>C) in a solid-particle solar receiver. Chemical and sensible energy stored in the reduced perovskite particles is released as needed to a supercritical CO<span class=\"etd-inline-math\"><sub>2</sub></span> power cycle via re-oxidation and cooling of the material. Thermodynamics of Ca<span class=\"etd-inline-math\"><sub>1-x</sub></span>Sr<span class=\"etd-inline-math\"><sub>x</sub></span>MnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span> ($x=0.05$ and $0.1$) and CaCr<span class=\"etd-inline-math\"><sub>y</sub></span>Mn<span class=\"etd-inline-math\"><sub>1-y</sub></span>O<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span> ($y=0.05$ and $0.1$) are characterized through thermogravimetric analysis and calorimetry. Results indicate Ca<span class=\"etd-inline-math\"><sub>1-x</sub></span>Sr<span class=\"etd-inline-math\"><sub>x</sub></span>MnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span> compositions can store over 200 kJ kg<span class=\"etd-inline-math\"><sup>-1</sup></span> more specific energy storage compared to inert particulate TES media for <span class=\"etd-inline-math\">T \\ge 900<sup>\\</sup>circ</span>C; the specific energy storage potential of Ca<span class=\"etd-inline-math\"><sub>0.9</sub></span>Sr<span class=\"etd-inline-math\"><sub>0.1</sub></span>MnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span> at <span class=\"etd-inline-math\">T=900<sup>\\</sup>circ</span>C and <span class=\"etd-inline-math\">P<sub>\\</sub>text{O2}=10<sup>-4</sup></span> bar is 706 kJ kg<span class=\"etd-inline-math\"><sup>-1</sup></span>. Challenges are expected achieving these high values of energy storage in a transport-limited receiver with low residence time for CSP. Redox kinetics are explored in a packed bed reactor with rapid heating capabilities. Results in isothermal tests show that oxidation is significantly faster than reduction. Modeling of packed bed experiments indicate that reduction at <span class=\"etd-inline-math\">T \\ge 800<sup>\\</sup>circ</span>C is limited by build-up of oxygen in the gas phase and equilibrium thermodynamics between the solid and gas phases. Long-term redox cycling tests, which simulate a nominal TCES cycle, demonstrate excellent chemical stability for all materials. A standard deviation of 1.9\\% on the extent of reduction over 1000 cycles was observed for Ca<span class=\"etd-inline-math\"><sub>0.9</sub></span>Sr<span class=\"etd-inline-math\"><sub>0.1</sub></span>MnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span>. Modeling efforts of the packed bed experiments allow for characterization of redox kinetics, to be implemented in computational models for system component design. One of the most promising compositions, Ca<span class=\"etd-inline-math\"><sub>0.9</sub></span>Sr<span class=\"etd-inline-math\"><sub>0.1</sub></span>MnO<span class=\"etd-inline-math\"><sub>3-&delta;</sub></span>, is implemented in a 1-D receiver model to explore designs and operating conditions for perovskite-based energy storage systems.","abstract_has_math":true,"creators":["Imponenti, Luca"],"institution":"Colorado School of Mines. Arthur Lakes Library","degree_name":"Doctor of Philosophy (Ph.D.)","degree_level":"Doctoral","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Jackson, Gregory"],"committee_chairs":[],"committee_members":["O'Hayre, Ryan P.","Kee, R. J.","Braun, Robert J."],"year":2018,"date_issued":"2018","date_published":"2018","updated_at":"2026-07-24T01:42:34Z","subjects":["concentrated solar power","redox cycles","calcium manganite","thermochemical energy storage","perovskite"],"languages":["eng","English"],"rights":["Copyright of the original work is retained by the author."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["T 8625"],"render_values":[{"text":"T 8625","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/11124/172807","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Jackson, Gregory"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["O'Hayre, Ryan P.","Kee, R. J.","Braun, Robert J."]},{"key":"dc:creator","label":"Author","values":["Imponenti, Luca"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2018-12-12T23:07:47Z","2022-02-03T13:11:06Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2018-12-12T23:07:47Z","2022-02-03T13:11:06Z"]},{"key":"dc:date.issued","label":"Date","values":["2018"]},{"key":"dc:publisher","label":"Institution","values":["Colorado School of Mines. Arthur Lakes Library"]},{"key":"dc:type","label":"Dc Type","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (Ph.D.)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Colorado School of Mines"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["concentrated solar power","redox cycles","calcium manganite","thermochemical energy storage","perovskite"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright of the original work is retained by the author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["Imponenti_mines_0052E_11632.pdf","T 8625"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/11124/172807"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliographical references.","2018 Fall."]},{"key":"dc:description.abstract","label":"Abstract","values":["Redox cycles with reducible perovskite oxides of the form ABO$_3$ can provide thermochemical energy storage (TCES) with higher energy density and storage temperatures than molten-salt systems for large-scale energy storage in concentrating solar power (CSP). Perovskites from earth abundant cations are desirable for cost-effective solutions, but such materials must demonstrate appropriate thermodynamics for high specific TCES and favorable kinetics for heat-driven reduction and exothermic re-oxidation. This dissertation explores the thermodynamics and kinetics of doped CaMnO$_{3-\\delta}$ particles for TCES redox cycles where particles are heated and reduced in N$_2$ ($P_{\\text{O2}} \\approx 10^{-4}$ bar) to high temperatures (700 to $1000^{\\circ}$C) in a solid-particle solar receiver. Chemical and sensible energy stored in the reduced perovskite particles is released as needed to a supercritical CO$_2$ power cycle via re-oxidation and cooling of the material. Thermodynamics of Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ ($x=0.05$ and $0.1$) and CaCr$_y$Mn$_{1-y}$O$_{3-\\delta}$ ($y=0.05$ and $0.1$) are characterized through thermogravimetric analysis and calorimetry. Results indicate Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ compositions can store over 200 kJ kg$^{-1}$ more specific energy storage compared to inert particulate TES media for $T \\ge 900^\\circ$C; the specific energy storage potential of Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$ at $T=900^\\circ$C and $P_\\text{O2}=10^{-4}$ bar is 706 kJ kg$^{-1}$. Challenges are expected achieving these high values of energy storage in a transport-limited receiver with low residence time for CSP. Redox kinetics are explored in a packed bed reactor with rapid heating capabilities. Results in isothermal tests show that oxidation is significantly faster than reduction. Modeling of packed bed experiments indicate that reduction at $T \\ge 800^\\circ$C is limited by build-up of oxygen in the gas phase and equilibrium thermodynamics between the solid and gas phases. Long-term redox cycling tests, which simulate a nominal TCES cycle, demonstrate excellent chemical stability for all materials. A standard deviation of 1.9\\% on the extent of reduction over 1000 cycles was observed for Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$. Modeling efforts of the packed bed experiments allow for characterization of redox kinetics, to be implemented in computational models for system component design. One of the most promising compositions, Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$, is implemented in a 1-D receiver model to explore designs and operating conditions for perovskite-based energy storage systems."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["born digital","doctoral dissertations"]},{"key":"dc:title","label":"Title","values":["Redox cycles with doped calcium manganites for high-temperature thermochemical energy storage in concentrating solar power"]}]}],"canonical_facts":{"dc:contributor.advisor":["Jackson, Gregory"],"dc:contributor.committeemember":["O'Hayre, Ryan P.","Kee, R. J.","Braun, Robert J."],"dc:creator":["Imponenti, Luca"],"dc:date.accessioned":["2018-12-12T23:07:47Z","2022-02-03T13:11:06Z"],"dc:date.available":["2018-12-12T23:07:47Z","2022-02-03T13:11:06Z"],"dc:date.issued":["2018"],"dc:description":["Includes bibliographical references.","2018 Fall."],"dc:description.abstract":["Redox cycles with reducible perovskite oxides of the form ABO$_3$ can provide thermochemical energy storage (TCES) with higher energy density and storage temperatures than molten-salt systems for large-scale energy storage in concentrating solar power (CSP). Perovskites from earth abundant cations are desirable for cost-effective solutions, but such materials must demonstrate appropriate thermodynamics for high specific TCES and favorable kinetics for heat-driven reduction and exothermic re-oxidation. This dissertation explores the thermodynamics and kinetics of doped CaMnO$_{3-\\delta}$ particles for TCES redox cycles where particles are heated and reduced in N$_2$ ($P_{\\text{O2}} \\approx 10^{-4}$ bar) to high temperatures (700 to $1000^{\\circ}$C) in a solid-particle solar receiver. Chemical and sensible energy stored in the reduced perovskite particles is released as needed to a supercritical CO$_2$ power cycle via re-oxidation and cooling of the material. Thermodynamics of Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ ($x=0.05$ and $0.1$) and CaCr$_y$Mn$_{1-y}$O$_{3-\\delta}$ ($y=0.05$ and $0.1$) are characterized through thermogravimetric analysis and calorimetry. Results indicate Ca$_{1-x}$Sr$_x$MnO$_{3-\\delta}$ compositions can store over 200 kJ kg$^{-1}$ more specific energy storage compared to inert particulate TES media for $T \\ge 900^\\circ$C; the specific energy storage potential of Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$ at $T=900^\\circ$C and $P_\\text{O2}=10^{-4}$ bar is 706 kJ kg$^{-1}$. Challenges are expected achieving these high values of energy storage in a transport-limited receiver with low residence time for CSP. Redox kinetics are explored in a packed bed reactor with rapid heating capabilities. Results in isothermal tests show that oxidation is significantly faster than reduction. Modeling of packed bed experiments indicate that reduction at $T \\ge 800^\\circ$C is limited by build-up of oxygen in the gas phase and equilibrium thermodynamics between the solid and gas phases. Long-term redox cycling tests, which simulate a nominal TCES cycle, demonstrate excellent chemical stability for all materials. A standard deviation of 1.9\\% on the extent of reduction over 1000 cycles was observed for Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$. Modeling efforts of the packed bed experiments allow for characterization of redox kinetics, to be implemented in computational models for system component design. One of the most promising compositions, Ca$_{0.9}$Sr$_{0.1}$MnO$_{3-\\delta}$, is implemented in a 1-D receiver model to explore designs and operating conditions for perovskite-based energy storage systems."],"dc:format.medium":["born digital","doctoral dissertations"],"dc:identifier":["Imponenti_mines_0052E_11632.pdf","T 8625"],"dc:identifier.uri":["https://hdl.handle.net/11124/172807"],"dc:language":["English"],"dc:language.iso":["eng"],"dc:publisher":["Colorado School of Mines. Arthur Lakes Library"],"dc:rights":["Copyright of the original work is retained by the author."],"dc:subject":["concentrated solar power","redox cycles","calcium manganite","thermochemical energy storage","perovskite"],"dc:title":["Redox cycles with doped calcium manganites for high-temperature thermochemical energy storage in concentrating solar power"],"dc:type":["Text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy (Ph.D.)"],"thesis:institution_name":["Colorado School of Mines"]},"updated_at":"2026-07-24T01:42:34Z"}