Search NASA⌕ Search

SEARCH · Search NASA

Results for “MnO 2”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Highly textured metal anodes for stable aqueous batteries: Fabrication and characterization

We report a purely mechanical “cold-compression flow” method for fabricating Zn, Sn, and In substrates with tunable crystallographic textures. Using textured Zn as a model system, we investigate Zn electrocrystallization and demonstrate correlated growth of crystalline films with correlation lengths from tens to hundreds of micrometers. At 5 milliamperes per square centimeter (mA/cm 2 ), capacities between 20 and 82 milliampere hours per square centimeter (mA·hour/cm 2 ) are achieved depending on substrate texture level. At higher currents (40 mA/cm 2 ), capacities reach up to 604 mA·hour/cm 2 . Rotating disk electrode studies show that dominantly (002) textured Zn substrates exhibit enhanced corrosion resistance and reduced interphase passivation. We introduce an effective Damköhler number (Da*) to concisely describe morphological evolution during electrocrystallization across substrates with different textures. High-texture (002) Zn substrates substantially enhance performance in high-capacity (~20 mA·hour/cm 2 ) symmetric Zn||Zn cells and full cells (Zn||δ-MnO 2 and Zn||I 2 ), enabling fast-charging and prolonged energy storage in coin and pouch rechargeable Zn battery formats.

Science & Technology - Other Topics↗
DOE OSTI2023

Engineering In Situ Catalytic Cleaning Membrane Via Prebiotic-Chemistry-Inspired Mineralization

Pressure-driven membrane separation promises a sustainable energy-water nexus but is hindered by ubiquitous fouling. Natural systems evolved from prebiotic chemistry offer a glimpse of creative solutions. Herein, a prebiotic-chemistry-inspired aminomalononitrile (AMN)/Mn 2+ -mediated mineralization method is reported for universally engineering a superhydrophilic hierarchical MnO 2 nanocoating to endow hydrophobic polymeric membranes with exceptional catalytic cleaning ability. Green hydrogen peroxide catalytically triggered in-situ cleaning of the mineralized membrane and enabled operando flux recovery to reach 99.8%. The mineralized membrane exhibited a 9-fold higher recovery compared to the unmineralized membrane, which is attributed to active catalytic antifouling coupled with passive hydration antifouling. Electron density differences derived from the precursor interaction during mediated mineralization unveiled an electron-rich bell-like structure with an inner electron-deficient Mn core. This work paves the way to construct multifunctional engineered materials for energy-efficient water treatment as well as for diverse promising applications in catalysis, solar steam generation, biomedicine, and beyond.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Intercalative Redox Tuning for Cu/Li x Mn 2 O 4 -Catalyzed Oxidative Alkyne Coupling

Modulation of heterogeneous catalyst structure is ubiquitous within efforts to improve catalytic activity and selectivity at the molecular level. Herein, manganese oxide (MnO 2 ) is employed as a continuously tunable catalyst support through increasing extent of lithium intercalation and reduced surface potential. Oxidative grafting of an organocopper complex onto various lithium manganese oxides (Li x Mn 2 O 4 , x = 0-2.1) produced divalent and monovalent copper species on the partially reduced (0 ≤ x ≤ 1.2) and fully reduced (x = 2.1) surfaces, respectively, as determined by X-ray absorption fine structure (XAFS) analysis. In this study, the resultant materials are catalytically active for the oxidative coupling of terminal alkynes, with steady-state reaction rate data of oxidative propyne dimerization (200 °C, 0.6-2.4 kPa propyne, 2.4-9.9 kPa O 2 ) indicating that complete support lithiation (Li 2.1 Mn 2 O 4 ) provides increased catalytic performance and renders reoxidation steps less kinetically demanding compared to the unreduced parent material. Enacting a dual site (Cu and MnO x ) kinetic model can account for dimerization rates measured over Cu/Li 2.1 Mn 2 O 4 under various reactant concentrations, copper loadings, and surface coverages, providing supporting evidence for the synergistic role of the metal and support in facilitating the coupling reaction. Overall, results presented here provide an extension for general strategies of systematically controlling catalytic structure and function through lithium reduction of bulk oxides and subsequent electronic modulation of the metals supported thereon.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Expanding the Material Search Space for Multivalent Cathodes

Multivalent batteries are an energy storage technology with the potential to surpass lithium-ion batteries; however, their performance have been limited by the low voltages and poor solid-state ionic mobility of available cathodes. A computational screening approach to identify high-performance multivalent intercalation cathodes among materials that do not contain the working ion of interest has been developed, which greatly expands the search space that can be considered for material discovery. This approach has been applied to magnesium cathodes as a proof of concept, and four resulting candidate materials [NASICON V 2 (PO 4 ) 3 , birnessite NaMn 4 O 8 , tavorite MnPO 4 F, and spinel MnO 2 ] are discussed in further detail. In examining the ion migration environment and associated Mg 2+ migration energy in these materials, local energy maxima are found to correspond with pathway positions where Mg 2+ passes through a plane of anion atoms. While previous studies have established the influence of local coordination on multivalent ion mobility, these results suggest that considering both the type of the local bonding environment and available free volume for the mobile ion along its migration pathway can be significant for improving solid-state mobility.

25 ENERGY STORAGE↗
DOE OSTI2023

Low cobalt layered oxide materials for lithium ion battery electrodes

Stabilized layered lithium metal oxide cathode materials are described which include excess lithium, Ni, Mn, and at least one other metal ion. The materials comprise a layered LiMO 2 -type material in which M comprises a combination of Ni, Mn, and at least one other metal ion that includes less than about 6 mol % Co; and which has about 1 to 6 percent excess lithium. In one embodiment, the stabilized lithium metal oxide cathode material comprises a composition having the empirical formula xLi 2 MnO 3 ·(1−x)LiNi 0.5+δ/2 Mn 0.5−δ Co δ/2 O 2 , wherein 0 1+3y [Ni a Mn b M′ c ] 1−y O 2 , wherein M′ is one of more metal selected from the group consisting of Co, Al, Fe, Mg, and Ti; 0<y≤0.02; 0.85≤a≤0.96; 0.03≤b≤0.1; and 0.01≤c≤0.1.

Croy, Jason R.↗
DOE OSTI2021

Evaluations of the Fates of Alkali Metals, Actinides, Mercury, and Iodine During DWPF Recycle Diversion

The fates of alkali metals, actinides, mercury, and iodine in the Defense Waste Processing Facility Recycle Diversion process (as currently conceptualized) have been evaluated through paper studies based on available knowledge of the chemistry, physical properties, solubility, and volatility of the various species involved. The effect of pH in the range from 9 to 13 has been discussed. Recommendations for additional studies to close technology gaps have been provided, many of which are contingent upon the results of pending testing and sample characterization efforts. There is uncertainty in the amounts of soluble actinides passing through the process filter, though the bulk of the actinides should be captured on the filter with the Recycle Collection Tank solids and the total amounts of actinides should be relatively low. The Recycle Collection Tank pH could impact the fraction of actinides reaching the evaporator, but the primary factors determining the actinide fate are expected to be the amount of CO 2 sorption from air sparging or, for certain actinides (such as plutonium), oxidation and/or sorption to MnO 2 solids from permanganate additions to destroy the glycolate anion. Process optimization could minimize the amounts of actinides passing the filter. Depending upon the levels of mercury observed in recycle stream samples and because of the volatility of mercury, the evaporator should be designed with the capability to remove dense mercury phases from the condensate to avoid exceeding ETP WAC limits. The facility design must be adequate to transfer dense mercury phases and testing to confirm mercury transfer is needed. Simulant containing mercury is recommended for both filtration and evaporation testing. OLI Modeling of the various recycle streams is recommended to provide insight on the fate of iodine. Iodine-spiked simulants are recommended for upcoming evaporation tests. The pro) ect should consider the likelihood and impact of NAS scale formation in the evaporators. Process optimization may be needed to minimize the accumulation of NAS scale and possibly the sorption of actinides in the evaporator. Actual waste testing of the Recycle Diversion filtration and evaporation should include the analysis of actinides, mercury, and iodine to determine their partitioning.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Elastic Lattice Enabling Reversible Tetrahedral Li Storage Sites in a High-Capacity Manganese Oxide Cathode

The key to breaking through the capacity limitation imposed by intercalation chemistry lies in the ability to harness more active sites that can reversibly accommodate more ions (e.g., Li + ) and electrons within a finite space. However, excessive Li-ion insertion into the Li layer of layered cathodes results in fast performance decay due to the huge lattice change and irreversible phase transformation. Here, in this study, an ultrahigh reversible capacity is demonstrated by a layered oxide cathode purely based on manganese. Through a wealth of characterizations, it is clarified that the presence of low-content Li 2 MnO 3 domains not only reduces the amount of irreversible O loss; but also regulates Mn migration in LiMnO 2 domains, enabling elastic lattice with high reversibility for tetrahedral sites Li-ion storage in Li layers. This work utilizes bulk cation disorder to create stable Li-ion-storage tetrahedral sites and an elastic lattice for layered materials, with a reversible capacity of 600 mA h g –1 , demonstrated in th range 0.6–4.9 V versus Li/Li + at 10 mA g –1 . Admittedly, discharging to 0.6 V might be too low for practical use, but this exploration is still of great importance as it conceptually demonstrates the limit of Li-ions insertion into layered oxide materials.

25 ENERGY STORAGE↗
DOE OSTI2025

Pristine Interface between Lithium Lanthanum Zirconate and Lithium Manganese Oxide by Pulsed Laser Deposition

Solid state lithium-ion batteries have garnered increasing interest in recent years due to several potential advantages over liquid-electrolyte based systems. The possibility of integrating the lithium garnet oxide, Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO), with the high voltage cathode, spinel Li x Mn 2 O 4 (LMO), is evaluated here. Thin film bilayer structures are prepared by pulsed laser deposition on MgO (001) substrates and characterized by x-ray diffraction and transmission electron microscopy. The LLZTO is grown by an alternating layer-by-layer deposition of LLZTO and Li 3 N and subsequently annealed for several hours at 575 °C to promote crystallinity. Growth of crystalline LMO with a pristine interface to LLZTO is achieved by gentle heat treatment (500 °C) to remove surface carbonate from the electrolyte and by cathode growth at a low temperature of 250 °C. Higher temperature depositions (330 – 450 °C) result in reaction between the two materials and the appearance of Li 2 MnO 3 , which may be in part due to the presence of excess lithium in the electrolyte layer. Because fully lithiated LiMn 2 O 4 has a voltage of ≈3.7 V versus Li+/Li, the observation of a well-defined interface, free of impurity phases and with no interdiffusion of elements, indicates LLZTO is stable to at least 3.7 V.

Garnet LLZO↗
DOE OSTI2023

Nanocellulose‐Carboxymethylcellulose Electrolyte for Stable, High‐Rate Zinc‐Ion Batteries

Abstract Aqueous Zn ion batteries (ZIBs) are one of the most promising battery chemistries for grid‐scale renewable energy storage. However, their application is limited by issues such as Zn dendrite formation and undesirable side reactions that can occur in the presence of excess free water molecules and ions. In this study, a nanocellulose‐carboxymethylcellulose (CMC) hydrogel electrolyte is demonstrated that features stable cycling performance and high Zn 2+ conductivity (26 mS cm −1 ), which is attributed to the material's strong mechanical strength (≈70 MPa) and water‐bonding ability. With this electrolyte, the Zn‐metal anode shows exceptional cycling stability at an ultra‐high rate, with the ability to sustain a current density as high as 80 mA cm −2 for more than 3500 cycles and a cumulative capacity of 17.6 Ah cm −2 (40 mA cm −2 ). Additionally, side reactions, such as hydrogen evolution and surface passivation, are substantially reduced due to the strong water‐bonding capacity of the CMC. Full Zn||MnO 2 batteries fabricated with this electrolyte demonstrate excellent high‐rate performance and long‐term cycling stability (>500 cycles at 8C). These results suggest the cellulose‐CMC electrolyte as a promising low‐cost, easy‐to‐fabricate, and sustainable aqueous‐based electrolyte for ZIBs with excellent electrochemical performance that can help pave the way toward grid‐scale energy storage for renewable energy sources.

25 ENERGY STORAGE↗
DOE OSTI2020

Architecting a Stable High-Energy Aqueous Al-Ion Battery

Aqueous Al-ion batteries (AAIBs) are the subject of great interest due to the inherent safety and high theoretical capacity of aluminum. The high abundancy and easy accessibility of aluminum raw materials further make AAIBs appealing for grid-scale energy storage. However, the passivating oxide film formation and hydrogen side reactions at the aluminum anode as well as limited availability of the cathode lead to low discharge voltage and poor cycling stability. Here, we proposed a new AAIB system consisting of an Al x MnO 2 cathode, a zinc substrate-supported Zn-Al alloy anode, and an Al(OTF) 3 aqueous electrolyte. Through the in situ electrochemical activation of MnO, the cathode was synthesized to incorporate a two-electron reaction, thus enabling its high theoretical capacity. The anode was realized by a simple deposition process of Al 3+ onto Zn foil substrate. The featured alloy interface layer can effectively alleviate the passivation and suppress the dendrite growth, ensuring ultralong-term stable aluminum stripping/plating. The architected cell delivers a record-high discharge voltage plateau near 1.6 V and specific capacity of 460 mAh g -1 for over 80 cycles. Finally, this work provides new opportunities for the development of high-performance and low-cost AAIBs for practical applications.

25 ENERGY STORAGE↗
DOE OSTI2020

Bismuth Enables the Formation of Disordered Birnessite in Rechargeable Alkaline Batteries

Recent advances in rechargeable Zn/MnO$_2$ alkaline batteries have shown promise for scalable energy storage systems which provide a safe, low-cost alternative with a demonstrated lifetime over thousands of cycles. This cathode technology is based on a 2-electron Mn redox process where a layered birnessite-type phase has been shown to form after the first cycle with excellent reversibility between the discharge product, Mn(OH)$_2$. Herein, we investigate the reversible reaction between birnessite and Mn(OH)$_2$ with and without a Bi$_2$O$_3$ additive using multimodal structural characterization techniques during active battery cycling. Diffraction results provide evidence of Bi$^{3+}$ residing in the interlayer of birnessite which prevents irreversible Mn$_3$O$_4$ formation by limiting Mn$^{3+}$ diffusion within the crystal lattice. Also, upon charge no MnOOH intermediate phases are observed. Instead, X-ray absorption and Raman spectroscopy indicate a disordered, non-crystalline birnessite-type phase consisting of mostly neutral H$_2$O within the interlayer. Birnessite phases will reform without Bi$_2$O$_3$ present, but Mn$_3$O$_4$ formation severely polarizes the potential they are formed at, leading to capacity fade. Also, we discuss the reversible Bi$_2$O$_3$ conversion to Bi$^0$ and its contribution to the observed capacity. We expect the results will provide crucial insight into the development of aqueous, rechargeable battery systems utilizing MnO 2 .

25 ENERGY STORAGE↗
DOE OSTI2025

Tuning effect of vanadium substitution on the structural and electronic properties of potassium hollandite surfaces

Metal oxide surfaces possess unique properties that are crucial for a wide variety of applications. Herein, density functional theory calculations are performed to study surfaces of potassium hollandite, KMn 8 O 16 , a promising cathode material for electrochemical energy storage, and the vanadium-substituted analog KMn 7 VO 16 . The results show that there is a clear increase in the stability of KMn 8 O 16 with (001) < (110) < (100) or (010), apt to adopt an elongated rod-like morphology. The vanadium (V)-substitution lowers the crystal symmetry and prefers to occupy the surface sites, resulting in electron redistribution and selective tuning of surface energy depending on the surface structures. In particular, the higher stability of substituted V 4+ compared with Mn 4+ ions leads to stabilization of the (001) surface due to the direct interaction of reduced Mn δ+ ions on the surface, while such tuning effect decreases with the increase in surface stability, (110) > (100) and (010). As a result, the KMnO 16 rod is shortened upon V-substitution as observed experimentally, effectively facilitating the ion transport during discharge. The V substituents also introduce stabilization to the defect surfaces resulting from Mn 2+ dissolution during cycling, thereby hindering further structural decay. In conclusion, our study demonstrates the potential tuning effect of V-substitution to promote the ion transport and mitigate the capacity degradation of α-MnO 2 -based materials.

25 ENERGY STORAGE↗
DOE OSTI2021

2D Ni 0.25 Mn 0.75 O 2 : A high-performance cathode for multivalent ion batteries

Although Li-ion batteries have driven portable energy storage in recent decades, there is increasing concern about their safety, cost, and abundance of constituents. Multivalent ion batteries (MVIBs) have the potential to remedy these issues, but they are limited by the currently known MVIB cathodes, which fail to deliver unanimously favorable voltage, energy density, and diffusion kinetics. Here we used density functional theory (DFT) to model the performance of Li, Na, Mg, Ca, and Al ions when paired with 2D Ni 0.25 Mn 0.75 O 2 , a novel cathode that uses increased layer separation to improve on the kinetics of its 3D analog. Our calculations yielded maximum voltages of 3.38 V for Na and 2.7 V for Ca, outperforming 2D Na x MnO 2 and Na x NiO 2 . Diffusion barriers for Li, Na, and Ca are below 300 meV, comparable to existing battery technology and the endpoint 2D cathodes; meanwhile, Mg and Al have prohibitively high diffusion barriers, implying their incompatibility with this cathode. Lastly, density of states calculations and Bader charge analysis show that the cathode becomes conducting following ion adsorption, which is necessary for high-rate performance. 2D Ni 0.25 Mn 0.75 O 2 maintains performance seen with other 2D transition metal oxides while increasing cathode conductivity, indicating that it is a promising candidate for experimental investigation with Li, Na, and Ca ions.

25 ENERGY STORAGE↗
DOE OSTI2021

Production of synthesis gas from natural gas with copper—iron—manganese oxide oxygen carriers/catalysts via partial oxidation and dry reforming processes

Materials, methods of making, and methods of providing a trimetallic oxygen carrier for converting methane containing fuel to synthesis gas. The trimetallic oxygen carrier comprises CuxFeyMnzOt, where CuxFeyMnzOt is a chemical composition with 0 < x ≤ 3 and 0 < y ≤ 3 and 0 < z ≤ 3 and, 0 < t ≤ 5. For example, CuxFeyMnzOt may be one of CuMnFeO 4 , CuFe 0.5 Mn 1.5 O 4 , CuFeMn 2 O 4 , CuFe 2 MnO 4 , or Cu impregnated on FerMnsOu, Fe impregnated on CurMnsOu, Mn impregnated on CurFesOu where r > 0, s > 0 and u > 0 and combinations thereof. Reaction of trimetallic CuxFeyMnzOt with methane generates a product stream comprising at least 50 vol. % CO and H 2 .

Siriwardane, Ranjani V.↗
DOE OSTI2023

Elucidating a dissolution–deposition reaction mechanism by multimodal synchrotron X-ray characterization in aqueous Zn/MnO 2 batteries

Aqueous Zn/MnO 2 batteries with their environmental sustainability and competitive cost, are becoming a promising, safe alternative for grid-scale electrochemical energy storage. Here, presented as a promising design principle to deliver a higher theoretical capacity, this work offers fundamental understanding of the dissolution–deposition mechanism of Zn/β-MnO 2 . A multimodal synchrotron characterization approach including three operando X-ray techniques (powder diffraction, absorption spectroscopy, and fluorescence microscopy) is coupled with elementally resolved synchrotron X-ray nano-tomography. Together they provide a direct correlation between structural evolution, reaction chemistry, and 3D morphological changes. Operando synchrotron X-ray diffraction and spectroscopy show a crystalline-to-amorphous phase transition. Quantitative modeling of the operando data by Rietveld refinement for X-ray diffraction and multivariate curve resolution (MCR) for X-ray absorption spectroscopy are used in a complementary fashion to track the structural and chemical transitions of both the long-range (crystalline phases) and short-range (including amorphous phases) ordering upon cycling. Scanning X-ray microscopy and full-field nano-tomography visualizes the morphology of electrodes at different electrochemical states with elemental sensitivity to spatially resolve the formation of the Zn- and Mn-containing phases. Overall, this work critically indicates that for Zn/MnO 2 aqueous batteries, the reaction pathways involving Zn–Mn complex formation upon cycling become independent of the polymorphs of the initial electrode and sheds light on the interplay among structural, chemical, and morphological evolution for electrochemically driven phase transitions.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Membrane-Free Zn/MnO 2 Flow Battery for Large-Scale Energy Storage

The traditional Zn/MnO 2 battery has attracted great interest due to its low cost, high safety, high output voltage, and environmental friendliness. However, it remains a big challenge to achieve long-term stability, mainly owing to the poor reversibility of the cathode reaction. Different from previous studies where the cathode redox reaction of MnO 2 /MnOOH is in solid state with limited reversibility, in this work a new aqueous rechargeable Zn/MnO 2 flow battery is constructed with dissolution–precipitation reactions in both cathodes (Mn 2+ /MnO 2 ) and anodes (Zn 2+ /Zn), which allow mixing of anolyte and catholyte into only one electrolyte and remove the requirement for an ion selective membrane for cost reduction. Impressively, this new battery exhibits a high discharge voltage of ≈1.78 V, good rate capability (10C discharge), and excellent cycling stability (1000 cycles without decay) at the areal capacity ranging from 0.5 to 2 mAh cm -2 . More importantly, this battery can be readily enlarged to a bench scale flow cell of 1.2 Ah with good capacity retention of 89.7% at the 500th cycle, displaying great potential for large-scale energy storage.

25 ENERGY STORAGE↗
DOE OSTI2021

Toward the Understanding of the Reaction Mechanism of Zn/MnO2 Batteries Using Non-alkaline Aqueous Electrolytes

Zn/MnO 2 systems using non-alkaline aqueous electrolytes have attracted tremendous interest as rechargeable aqueous Zn ion batteries due to their safety and high specific capacities. Despite their promising electrochemical performance, however, their reaction mechanism has remained elusive. Here in this paper, we examined the structural evolution of cryptomelane α-MnO 2 cathode by ex situ transmission electron microscopy after electrochemical testing using two different non-alkaline aqueous Zn electrolytes with acetate and triflate salts of different pH values. We have discovered that the systems tested in both electrolytes exhibit a dissolution–deposition reaction mechanism through dissolution–deposition of Mn 2+ ions from/on the cathodes with a display of similar discharge/charge product formation. We have also found that the cell tested using the acetate electrolyte shows evidence of structural irreversibility that might contribute to its rapid capacity degradation. This finding offers an important insight into optimizing the cathode design for enhanced electrochemical function of aqueous Zn/MnO 2 batteries.

25 ENERGY STORAGE↗