A chemically regenerative redox fuel cell

A novel chemically regenerative redox fuel cell is described. The electrode reactions are based on the following redox reactions: cathodic reaction: anodic reaction: VO ₂ ⁺ +2H⁺+e VO²⁺+H₂O (E ₀ +1V), SiW₁₂O ₄₀ ^5– SiW₁₂O ₄₀ ^4– +e (E ₀ 0V). Regeneration of the oxidant by direct oxidation with O₂ was achieved by using the soluble heteropoly acid catalysts, H₃PMo₁₂O₄₀ or H₅PMo₁₀V₂O₄₀, whereas regeneration of the tungstosilicic acid, H₃SiW₁₂O₄₀, was accomplished by direct reduction with H₂ utilizing small amounts of Pt, Pd, Rh, Ru or the soluble Pd-4, 4, 4, 4'-tetrasulphophthalocyanine complex as catalysts. Some aspects of the regeneration kinetics and their influence on the overall performance of the redox fuel cell are discussed.     

The redox mechanism of the chelate-catalysed oxygen cathode

The electro-reduction of oxygen is effectively catalysed by metal chelates of the N4-type. The mechanism of this process has been found to be a modified redox catalysis. O₂ molecules and the products of their reaction, at least up to H₂O₂, remain strongly co-ordinated to the central metal ion of the chelates XMe^II. The potential-determining step, which regenerates the reduced form, is the following: (XMe^III...O₂H)⁺+H⁺+ 2eXMe^II+H₂O₂.H₂O₂ is further decomposed via the catalase action of the electrocatalyst. The mechanism is confirmed by experimental results with iron phthalocyanine (FePc) and cobalt-dibenzotetraazaannulene (CoTAA) as a O₂-slurry electrode at various O₂ pressures. The latter shows anodic reaction-limited currents, which seem to involve also oxygen-containing intermediates. The implication of the presented mechanism in regard to other electrochemical processes is discussed briefly.     

Die kathodische reduktion von ozon in sauren elektrolyten

The cathodic reduction of ozone ?O₃ + 2H⁺ + 2e → H₂O + O₂ ? on bright platinum was investigated in sulphuric acid electrolytes. Rest potentials deviate from the reversible values by ?350 to ?400 mV. They are determined by a mixed potential mechanism involving anodic oxygen evolution and the cathodic ozone reduction as half-reactions. Steady state polarization measurements were carried out. Current densities at the rest potential, which are analogous to exchangecd, are obtained by extrapolation of Tafel-lines to zero overvoltage and by determination of the charge  transfer resistance. A single electron transfer reaction is found to be the rate-controlling step which is occurring twice for the reduction of one molecule of ozone. Cathodic reaction orders of +0,5 and + 1 are evaluated with respect to [H⁺] and [p_O3]. A reaction mechanism is proposed according to

which is consistent with experimental data.Limiting currents are observed in the region of high cathodic polarization, which are diffusion controlled.     

A Study on the Bonding Conditions and Mechanism for Glass-to-Glass Anodic Bonding in Field Emission Display

Here we have investigated the bonding conditions and mechanism for glass-to-glass anodic bonding in indium-tin-oxide (ITO)-coated glass using an Al/Cr composite thin film as an interlayer prepared by RF magnetron sputtering. The experimental results show that the bond strength increases with increasing the bonding temperature, bonding voltage, and Al film thickness. The optimum experimental parameters in the anodic bonding were found to be an Al film thickness of 300 nm, bonding temperature of 300°C, and bonding voltage of 700 V. Oxygen content within the bonded interphase increases and aluminum content decreases on increasing both the temperature and voltage during the bonding process. According to EDS analysis results, the main bond mechanism is proposed to be due to the following chemical reactions: 4Na⁺ + 4e^? → 4Na, xAl + yO^2? → Al _x O _y + 6e^?, x = 2, y = 3.     

On the promotional effect of Sn in Co–Sn/Al2O3 catalyst for NO selective reduction

NO reduction with propylene over Co/Al₂O₃ and Co–Sn/Al₂O₃ catalysts has been investigated. For the Co/Al₂O₃ catalyst, a calcination temperature exceeding 800°C led to a decrease of NO conversion. Calcination of the Co/Al₂O₃ catalyst at 1000°C resulted in the formation of -Al₂O₃ and Co₃O₄. The presence of 20% water vapor showed a significant shift for the maximum NO reduction temperature from 450 to 600°C over Co/Al₂O₃. It has been found that modification of 6 wt% Co/Al₂O₃ with 2 wt% Sn significantly enhanced the catalyst thermal stability and improved the inhibitory effect of water on NO conversion and reaction temperature. The promotional effect of Sn on the catalyst thermal stability was attributed to the suppression of the phase transformation from highly dispersed Co²⁺ species on -Al₂O₃ to -Al₂O₃ and Co₃O₄. The smaller influence of water vapor on NO reduction conversion and temperature over Co–Sn/Al₂O₃, compared to Co/Al₂O₃, was attributed to the dispersion effect of Sn species on Co²⁺ species as well as the involvement of Sn species in NO reduction at a relatively lower temperature. The synergetic effect between the octahedral Co²⁺ species and -alumina plays a significant role in the catalysis of NO selective reduction by C₃H₆.     

The solubility of selenate-AFt (3CaO·Al2O3·3CaSeO4·37.5H2O) and selenate-AFm (3CaO·Al2O3·CaSeO4·xH2O)

The Se(VI)-analogues of ettringite and monosulfate, selenate-AFt (3CaO·Al₂O₃·3CaSeO₄·37.5H₂O), and selenate-AFm (3CaO·Al₂O₃·CaSeO₄·xH₂O) were synthesised and characterised by bulk chemical analysis and X-ray diffraction. Their solubility products were determined from a series of batch and resuspension experiments conducted at 25 °C. For selenate-AFt suspensions, the pH varied between 11.37 and 11.61, and a solubility product, log K_so=61.29±0.60 (I=0 M), was determined for the reaction 3CaO·Al₂O₃·3CaSeO₄·37.5H₂O+12 H⁺⇔6Ca²⁺+2Al³⁺+3SeO₄²⁻+43.5H₂O. Selenate-AFm synthesis resulted in the uptake of Na, which was leached during equilibration and resuspension. For the pH range of 11.75 to 11.90, a solubility product, log K_so=73.40±0.22 (I=0 M), was determined for the reaction 3CaO·Al₂O₃·CaSeO₄·xH₂O+12 H⁺⇔4Ca²⁺+2Al³⁺+SeO₄²⁻+(x+6)H₂O. Thermodynamic modelling suggested that both selenate-AFt and selenate-AFm are stable in the cementitious matrix; and that in a cement limited in sulfate, selenate concentration may be limited by selenate-AFm to below the millimolar range above pH 12.     

Structure and Photoluminescence of A Blue‐Green‐Emitting Phosphor for Near‐UV White LEDs

A series of phosphors Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ have been prepared by a hightemperature solid‐state reaction using boric acid as flux. These oxyfluorides crystallize in cubic structure, space group. Under the near ultraviolet excitation within wavelength range 310–390 nm, Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ phosphors exhibit an intense emission covering a broad band of 370–500 nm derived from the 5d→4f transitions of Ce³⁺ and a characteristic emission at 544 nm of Tb³⁺. The emission can be tuned from blue to green by altering the relative ratio of Ce³⁺ to Tb³⁺ in the composition. The energy‐transfer mechanism from Ce³⁺ to Tb³⁺ is investigated based on the site occupancy of the luminescence center in the crystal structure of the Ca₁₂Al₁₄O₃₂F₂ host. More importantly, when a certain amount of boric acid is added as flux in the synthesis, the fluorescence intensity of the phosphors increases about 65%. Because of its broad excitation and efficiently tunable blue to green luminescence, the Ca_12(0.97?x)Al₁₄O₃₂F₂: 0.03Ce³⁺, xTb³⁺ phosphors may find promising application as a near UV‐convertible phosphor for white‐light‐emitting diodes.     

Control of Oxidation State of Eu Ions in Na2O–Al2O3–SiO2 Glasses

Glasses doped with well‐controlled Eu³⁺ and Eu²⁺ ions have attracted considerable interest due to the possibility of tuning the wavelength range of the emitted light from violet to red by using their ⁵D₀→⁷F_j and 5d–4f electron transitions. Glasses were prepared to dope Eu³⁺ ions in a Na₂O–Al₂O₃–SiO₂ system, and the changes in the valence state of Eu³⁺ ions and the glass structure surrounding the Eu atoms during heating under H₂ atmosphere were investigated using fluorescence spectroscopy, X‐ray absorption fine‐structure spectroscopy, and ²⁷Al magic‐angle spinning solid‐state nuclear magnetic resonance spectroscopy. The reduction behavior of Eu³⁺ ions was dependent on the Al/Na molar ratio of the glass. For Al/Na < 1, the Al³⁺ ions formed the AlO₄ network structure accompanied by the Na⁺ ions as charge compensators; the Eu³⁺ ions occupied the interstitial positions in the SiO₄ network structure and were not reduced even under heating in H₂ gas. On the other hand, in the glasses containing Al₂O₃ with the Al/Na ratio exceeding unity, the Eu³⁺ ions commenced to be coordinated by the AlO₄ units in addition to the SiO₄ network structure. When heated in H₂ gas, H₂ gas molecules reacted with the AlO₄ units surrounding Eu³⁺ ions to form AlO₆ units terminated with OH bonds, and reduced Eu³⁺ ions to Eu²⁺ via the extracted electrons.     

A DFT study of methanol oxidation on Co3O4

By means of spin polarized density functional theory with the GGA + U framework, the reaction mechanism of CH₃OH oxidation on the Co₃O₄ (110)-B and (111)-B surfaces has been investigated. Adsorption situation and a part of reaction cycle for CH₃OH oxidation are clarified. Our results indicated that: i) U value can affect the calculated energetic result significantly; ii) CH₃OH can adsorb with surface lattice oxygen atom (O_2f/O_3f) to form CoO bond directly, and the adsorption of CH₃OH and its decomposition products on (110)-B is more stable than on (111)-B, which means CH₃OH prefers Co^3 + better than Co^2 +; iii) on the (110)-B surface, CH₃OH can form CO₂, H₂O and adsorbed H atom. But on the (111)-B surface, CH₃OH can just form formaldehyde (CH₂O) and adsorbed H atom, this means oxidative capacity of (110)-B (Co^3 +) is higher than (111)-B (Co^2 +). The possible reasons corresponding to the high oxidative of (110)-B come from both Co^3 + and O_2f: Co^3 + tends to bind adsorbed species for further decomposition and O_2f tends to bind more hydrogenation atom involved in methanol due to its low-coordinates number compared to that of O_3f.     

Enhanced Light Storage of SrAl2O4 Glass‐Ceramics Controlled by Selective Europium Reduction

A luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O₂ partial pressure () for the oxidation of Eu²⁺ ions. The glass‐ceramics include Eu²⁺, Eu³⁺, and Dy³⁺ ions, and thus exhibits three characteristic types of emission bands, 4f–5d at around 520 nm (Eu²⁺ ions), 4f–4f at 610 nm (Eu³⁺ ions), and 480 nm (Dy³⁺ ions). The Eu, Dy: SrAl₂O₄ glass‐ceramics provide remarkable long‐persistent luminescence under dark condition. The glass‐ceramics also exhibits color‐changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl₂O₄ glass‐ceramics using the frozen sorbet technique with control of are promising materials for application in novel photonic and light storage materials.     

Fabrication of Naphthol green B/layered double hydroxide nanosheets ultrathin film and its application in electrocatalysis

A facile enzyme-free hydrogen peroxide electrochemical sensor was fabricated based on multilayer ultrathin film containing Naphthol green B anions (NGB) and exfoliated nanosheets of Co–Al layered double hydroxide (LDH) via layer-by-layer self-assembly technique. The X-ray diffraction pattern indicates the superlattice structure of the film with repeating distance of 4.15 nm; SEM and AFM images show that the film surface is continuous and uniform. The electrochemical behavior of the ultrathin film was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The ultrathin film modified electrode shows a fast direct electron transfer for the Co²⁺/Co³⁺ redox couple with ΔE = 14 mV in 0.1 M NaOH solution. Furthermore, the modified electrode displays a significant electrocatalytic performance for H₂O₂ with Michaelis–Menten constant . The anodic peak current increased linearly with the concentration of H₂O₂ from 8.0 × 10⁻⁶ to 1.8 × 10⁻⁴ M with a low detection limit of 9.0 × 10⁻⁷ M. The NGB/LDH ultrathin film was demonstrated as a feasible electrochemical sensor for detection of H₂O₂ with rapid response, high stability, good reproducibility and excellent selectivity.     

Comparative Study of the Synthesis and Properties of Polyoxometalate Pillared Layered Double Hydroxides (POM-LDHs)

The pillaring of (NO₃)-ZnAl-LDHs with the polyoxometalates (POMs) [PV₂W₁₀O₄₀]^5–, [Mo₇O₂₄]^6–, [V₁₀O₂₈]^6– and [H₂W₁₂O₄₀]^6–, using large organic anions like terephthalate for pre-swelling the LDH structure forms a promising method for the controlled creation of small micropores. The use of the terephthalate precursor ((T)-ZnAl-LDH) avoided almost completely the formation of undesired side phases during pillaring, although anion exchange with the large POM complexes proceeded with more difficulty than in the case where (NO₃)-LDHs were used as a starting material. Direct pillaring via the (NO₃)-LDHs resulted in multiphased materials, and no correlation was found between the M(II)/M(III) ratios in the starting LDHs and the created porosity. For the [POM]-ZnAl-LDHs pillared via the terephthalate precursor, the layer charge density arising from the amount of isomorphically substituted Al³⁺ in the LDH layers forms the crucial parameter with regard to the created microporosity. Improving the surface area (SA) and micropore volume (PV) values was accomplished by lowering the charge density on the LDH layers (increasing the Zn²⁺/Al³⁺ ratio). In this way, a [PV₂W₁₀O₄₀]-ZnAl-LDH (Zn²⁺/Al³⁺ = 4.26) with a SA (BET) of 166 m²/g and a PV of 0.047 cm³/g was formed.For the different types of pillars, small micropores were formed due to the pillaring process. In the case of the smaller POM complexes [Mo₇O₂₄]⁶⁺ and [V₁₀O₂₈]⁶⁺, an increase in PV and SA was not accompanied by a detectable shift in average pore size, which was the case for the second group of complexes, [PV₂W₁₀O₄₀]^5– and [H₂W₁₂O₄₀]^6–. Due to their larger dimensions, mainly micropores between 0.71 and 1.06 nm were created at high Zn²⁺/Al³⁺ ratios, together with a substantial amount of pores smaller than 0.71 nm.     

Electrodeposition of polypyrrole layers on aluminium from aqueous electrolytes

A screening of twenty aqueous electrolytes for a film-forming electropolymerization of pyrrole with Al was performed. Electrodeposition of well adhering homogeneous polypyrrole layers on aluminium is possible from aqueous electrolytes containing 0.1–0.8M oxalic acid. Pretreatment of the metal by polishing (PD) or by anodic (galvanostatic) activation (GA) is an essential step. In all cases, the Al₂O₃ surface layer with pores, usually filled with electrolyte, is transformed to a Al₂O₃ layer with polypyrrole filled pores. The PPy-layers on Al allow an easy cathodic coating with metals like copper. The hydrogenoxalate doped layers exhibit the ususal redox capacity,y=0.3. The sandwich structure Al/Al₂O₃/PPy represents a condenser with an unusual composite dielectric with the electronically conducting plates Al and PPy. According to our impedance measurements, the PPyin the pores is a high resistivity material due to overoxidation in the course of electropolymerization at high local current densities. The composite, Al₂O₃/overoxidized PPy, exhibits an unusually high permittivity, in the order of 10³.     

Thermal and chemical ionization in flames

Conclusions We have determined the rate constants of the potassium ionization process AA⁺+e^– in the flames of 2H₂+O₂+X (Ar, He) mixtures on the temperature interval 1500–2500° K. The activation energy of this process is close to the ionization potential of potassium (100 kcal).In our experiments the rate of ion formation in the front of a hydrogen flame seeded with potassium exceeded the purely thermal ionization rate by 0.5–2 orders. The presumed cause is recombination ionization of the potassium in the flame front, for example, K+O+OK⁺+O₂+e^–. This is confirmed by the intensification of ionization in the reaction zone in the presence of an excess of oxygen in homogeneous H₂-air and H₂–O₂–(He, Ar) mixtures with alkali impurities.At T=1700° K the recombination coefficient for electrons and potassium ions is close to 1·10^–8 cm³·sec^–1. For a more precise determination it is necessary to know the frequency of electron capture by molecules and atoms under the experimental conditions.Experiments on thermal ionization in turbulent flames confirm the earlier conclusion concerning the important role of mass transfer in the chemi-ionization of hydrocarbon flames.Fizika Goreniya i Vzryva, Vol. 6, No. 1, pp. 37–48, 1970     

Degree of Polymerization of Aluminosilicate Glasses and Melts

This paper presents the results of analyzing the data available in the literature on the structure and properties of silicate glasses and melts that contain Ti⁴⁺, Al³⁺, and Fe³⁺ cations in addition to alkali and alkaline-earth cations. It is established that the aforementioned multivalent cations in glasses and melts have a coordination number of four and play the role of network-formers. Aluminosilicate glasses and melts with the mole fraction ratio Al₂O₃/M ₂(M)O = 1 are of special interest. For these glasses, the structure is considered to be completely polymerized and, contrary to traditional concepts, their properties depend on the concentration ratio Al₂O₃/SiO₂. Taking into account that the structure of aluminosilicate glasses involves unusual structural units (such as triclusters) and a certain number of nonbridging oxygen atoms, a formula is proposed for calculating the degree of polymerization. The proposed formula is used to calculate the degree of polymerization for a number of Na₂O · Al₂O₃ · mSiO₂ glasses and the CaO · Al₂O₃ · 2SiO₂ glass. It is demonstrated that the calculated degrees of polymerization correlate with the experimentally measured viscosities of the relevant melts.     

High‐activity catalyst of SO 4 2− /ZrO2 supported on γ‐Al2O3 for n‐butane isomerization

A series of Al₂O₃supported SO ₄ ^2– /ZrO₂ superacid catalysts (named SZ/Al₂O₃) were prepared by a precipitation method and their catalytic behavior for nbutane isomerization at low temperature in the absence of H₂ and at high temperature in the presence of H₂ was studied in this paper. The catalytic activities of some of these catalysts were enhanced significantly at both low and high temperatures. At 250°C after 6 h on stream, the steady activity of the most active sample, 60%SZ/Al₂O₃, is about two times higher than that of conventional SZ. The texture properties of catalysts were studied by the methods of XRD and the adsorption of N₂. Experimental evidence of IR of adsorbed pyridine indicates that the significant activity enhancements of SZ/Al₂O₃ catalysts are caused by the increasing of the amount of strong acid sites.     

NO2 inhibits the catalytic reaction of NO and O2 over Pt

The rate equation for the overall reaction of NO and O₂ over Pt/Al₂O₃ was determined to be r=k_f[NO] ^1.05±0.08[O₂]^1.03±0.08[NO₂]^0.92±0.07(1-), with k_f as the forward rate constant, =([NO₂]/K[NO][O₂]^1/2), and K as the equilibrium constant for the overall reaction. An apparent activation energy of 82 kJ mol^–1 ± 9 kJ mol^–1 was observed. The inhibition by the product NO₂ makes it imperative to include the influence of NO₂ concentration in any analysis of the kinetics of this reaction. The reaction mechanism that fits our observed orders consists of the equilibrated dissociation of NO₂ to produce a surface mostly covered by oxygen, thereby inhibiting the equilibrium adsorption of NO, and the non-dissociative adsorption of O₂, which is the proposed rate determining step.     

On the electrochemical behavior of H2O2 AT Ag in alkaline solution

Electrochemical oxidation and reduction of H₂O₂ on Ag were studied in alkaline solution of 10^?3?0.3 M H₂O₂ and 2 × 10^?3 ?1.0 M KOH under N₂ bubbling. Steady i-φ curves obtained by a cyclic potential sweep method in a potential range where no electrode oxidation takes place, lead to the following results: (1) i^c_d (A cm^?2) (cathodic limiting current density) = 1.0 × [H₂O₂]^1.0_T (M), (2) i¹_d (A cm^?2 (anodic limiting one) = i^c_d ([KOH] ? [H₂O₂]_T) or 1.0 × [KOH] < [H₂O₂]_T), (3) φ_m (V) (mixed potential) = 0.126-0.060 log [KOH]^1.0 and (4) (?φ/?i)_φ=φm (Ωcm²) (reaction resistance at φ = φ_m) = 0.057 × [H₂O₂]^?1.0_T (M^?1), where [H₂O₂]_T designates a total H₂O₂ concentration and the others have their usual meanings.The above results are explained by the following mechanism; HO^?₂ formed by the reversible chemical reaction, H₂O₂ + OH ? HO^?₂ + H₂O, is oxidised in anodic reaction by two steps: HO^?₂

HO₂ (a) + e^? and HO₂(a) + OH^? → O₂ + H₂O + e^?, whereas in cathodic reaction, H₂O₂ is reduced by H₂O₂ + e^?

OH(a) + OH^?, OH(a) + e^? → OH^?. Here,

designates a rate determining step,Catalytic decomposition of H₂O₂ on the electrode is also discussed.     

Decomposition and oxidation of CH3 13CH2OH on A12O3, Pd/Al2O3, and PdO/Al2O3 catalysts

Temperature-programmed desorption (TPD) and oxidation (TPO) were used to investigate the decomposition and oxidation of ethanol on Al₂O₃, Pd/Al₂O₃, and PdO/Al₂O₃. Ethyl--¹³C alcohol (CH₃ ¹³CH₂OH) was adsorbed on the catalysts so that reaction pathways of the two carbons could be distinguished. Alumina was mainly a dehydration catalyst, but dehydrogenation was also observed and some carbon remained on the surface. In the presence of O₂, A1₂O₃ oxidized the decomposition products and the-carbon was oxidized faster. Ethanol, which was adsorbed on A1₂O₃, decomposed much faster on Pd/A1₂O₃ by diffusing to Pd and undergoing CO elimination to form CH₄,¹³CO, H₂, and surface carbon. On PdO/A1₂O₃, the decomposition was slower than on Pd/A1₂O₃ until lattice oxygen was extracted above 450 K; the decomposition products were oxidized by lattice oxygen. In the presence of gas phase O₂, Pd/Al₂O₃ was an active oxidation catalyst at low temperature, but lattice oxygen had to be extracted from PdO/A1₂O₃ before it had significant oxidation activity.     

Exploration of molten hydroxide electrochemistry for thermal battery applications

The electrochemistry of molten LiOH–NaOH, LiOH–KOH, and NaOH–KOH was investigated using platinum, palladium, nickel, silver, aluminum and other electrodes. The fast kinetics of the Ag⁺/Ag electrode reaction suggests its use as a reference electrode in molten hydroxides. The key equilibrium reaction in each of these melts is 2 OH^– = H₂O + O^2– where H₂O is the Lux-Flood acid (oxide ion acceptor) and O^2– is the Lux–Flood base. This reaction dictates the minimum H₂O content attainable in the melt. Extensive heating at 500 °C simply converts more of the alkali metal hydroxide into the corresponding oxide, that is, Li₂O, Na₂O or K₂O. Thermodynamic calculations suggest that Li₂O acts as a Lux–Flood acid in molten NaOH–KOH via the dissolution reaction Li₂O_(s) + 2 OH^– = 2 LiO^– + H₂O whereas Na₂O acts as a Lux–Flood base, Na₂O_(s) = 2 Na⁺ + O^2–. The dominant limiting anodic reaction on platinum in all three melts is the oxidation of OH^– to yield oxygen, that is 2 OH^– 1/2 O₂ + H₂O + 2 e^–. The limiting cathodic reaction in these melts is the reduction of water in acidic melts ([H₂O] [O^2–]) and the reduction of Na⁺ or K⁺ in basic melts. The direct reduction of OH^– to hydrogen and O^2– is thermodynamically impossible in molten hydroxides. The electrostability window for thermal battery applications in molten hydroxides at 250–300 °C is 1.5 V in acidic melts and 2.5 V in basic melts. The use of aluminum substrates could possibly extend this window to 3 V or higher. Preliminary tests of the Li–Fe (LAN) anode in molten LiOH–KOH and NaOH–KOH show that this anode is not stable in these melts at acidic conditions. The presence of superoxide ions in these acidic melts likely contributes to this instability of lithium anodes. Thermal battery development using molten hydroxides will likely require less active anode materials such as Li–Al alloys or the use of more basic melts. It is well established that sodium metal is both soluble and stable in basic NaOH–KOH melts and has been used as a reference electrode for this system.