Investigation on the Properties of the Mixture Consisting of Mg(NH₂)₂, LiH, and LiBH₄ as a Hydrogen Storage Material

A maximum hydrogen amount of 9.1 wt % was obtained at 300 °C from the 1Mg(NH2)2−2LiH−0.67LiBH4 system. Various analyses and thermodynamic calculations revealed that the MgH2 and LiNH2 can be readily converted to Mg(NH2)2 and LiH at 120 °C in the presence of LiBH4. A comparison between the sample 1Mg(NH2)2−2LiH−1LiBH4 and the ternary mixture 1MgH2−2LiNH2−1LiBH4 indicated that both samples behave very similarly in hydrogen desorption, thermal effects, and chemical changes during dehydrogenation

Additional file 3: of Multimodular type I polyketide synthases in algae evolve by module duplications and displacement of AT domains in trans

Amino acid sequences of newly annotated type I PKSs. (DOCX 25 kb

Introducing Interlayer Electrolytes: Toward Room-Temperature High-Potential Solid-State Rechargeable Fluoride Ion Batteries

Solid-state fluoride ion batteries (FIBs) promise high specific energy, thermal stability, and safety. Research on FIBs is in its infancy, and a number of issues still need to be addressed to realize its full potential. Progress on FIB strongly depends on developing suitable fluoride-ion-transporting electrolytes at room temperature (RT). BaSnF4 shows high ionic conductivity of 3.5 × 10–4 S cm–1 at RT. However, it has limited electrochemical stability window. Recently, we demonstrated RT rechargeable FIB utilizing BaSnF4 as a solid electrolyte and low electropositive metals, such as Sn and Zn metals, as anodes because of the limited electrochemical stability of BaSnF4, which results in low operating voltages. However, to enable cells with high operating potentials, the electrolyte should be compatible with highly electropositive metals (e.g., La, Ce). Although tysonite-type La0.9Ba0.1F2.9 electrolyte was shown to be compatible with such metals, it has the drawback of low ionic conductivity at RT (0.4 × 10–6 S cm–1). To overcome these limitations of the low electrolyte stability and low ionic conductivity, we applied an interlayer electrolyte to build FIB rather than pure electrolytes. A thin layer of La0.9Ba0.1F2.9 was pressed together with a thick layer of BaSnF4. Applying low-conductive La0.9Ba0.1F2.9 as thin layer enhanced the total conductance of the pellet (compared to pure La0.9Ba0.1F2.9), while it physically isolated the less stable and highly conductive electrolyte (BaSnF4) from the anode. This approach allowed the demonstration of relatively high voltage FIBs at RT, which can otherwise not operate either with BaSnF4 electrolyte alone. We optimized the total ionic conductivity of the interlayer electrolyte by altering the thickness of the La0.9Ba0.1F2.9 layer. The total ionic conductivity of interlayer electrolyte was increased to 0.89 × 10–5 S cm–1 for 45 μm thick La0.9Ba0.1F2.9 at RT, which is more than 1 order of magnitude higher compared to the pure La0.9Ba0.1F2.9 (0.4 × 10–6 S cm–1). Finally, we demonstrate the feasibility of operating FIB at RT utilizing the interlayer pellet as an electrolyte, BiF3 as a cathode and Ce as an anode material. The approach described here would enable the design and development of new solid electrolytes with advanced properties with existing electrolytes

Unlocking the Potential of Fluoride-Based Solid Electrolytes for Solid-State Lithium Batteries

The development of high energy density and sustainable all-solid-state lithium batteries relies on the development of suitable Li+ transporting solid electrolytes with high chemical and electrochemical stability, good interfacial compatibility, and high ionic conductivity. Ceramic-based electrolytes show high bulk Li+ conductivity and stability but exhibit poor mechanical properties. In contrast, a few sulfide-based electrolytes show high total Li+ conductivity and better mechanical properties but poor chemical and electrochemical stability. Moreover, both types of electrolytes exhibit interfacial compatibility issues with several electrode materials. Here, we reveal the potential of Li-containing metal fluorides as Li+ conducting solid electrolytes for solid-state lithium batteries, demonstrating their viability with a case study on β-Li3AlF6. We have synthesized β-Li3AlF6 by mechanical milling and investigated its properties as a solid electrolyte. An ionic conductivity of 3.9 × 10–6 S cm–1 was observed at 100 °C, which was increased to 1.8 × 10–5 S cm–1 by compositing with nanocrystalline alumina (γ-Al2O3). Furthermore, the performance of β-Li3AlF6 as a solid electrolyte was successfully tested in an all-solid-state lithium battery by using LiMn2O4 as a cathode and Li metal as an anode. Finally, we have used density functional theory to shed light on the Li diffusion pathways and associated activation barriers in β-Li3AlF6. Overall, our studies reveal the hidden potential of Li-containing metal fluorides as solid electrolytes for all-solid-state lithium batteries

Additional file 2: of Multimodular type I polyketide synthases in algae evolve by module duplications and displacement of AT domains in trans

Table S2. Details on analyzed type I PKSs and NRPSs. (XLSX 22 kb

Improving the Electrochemical Properties of Advanced Cross-Linked Solid Polymer Composite Electrolytes

Solid-state batteries based on composite polymer electrolytes (CPEs) have shown enormous potential for safe and high-energy-storage systems. The current work is focused on the study of a CPE based on cross-linked poly(ethylene glycol) (PEG) polymer and Li7La3Zr2O12 (LLZO) inorganic solid electrolyte. Nano- and micrometer-sized particles of LLZO were embedded in a cross-linked polymer that was synthesized via a solvent-free ring-opening polymerization technique. CPEs with nanosized LLZO were superior to the pure polymer or CPEs containing microsized particles. Different weight ratios of the nanosized LLZO in the polymer matrix influenced the electrochemical performance of the cells. CPE with 5 wt % LLZO showed significantly improved Li stripping/plating behavior. In contrast to the pure polymer electrolytes, where the voltage polarizations drastically increased after only 27 h of testing, nano-LLZO-5 wt %-CPE maintained stable voltage profiles at 0.05 mA cm2 for over 200 h. Furthermore, the addition of 5 wt % nano-LLZO yielded a wider electrochemical stability window (an increase of ∼1 V), higher transference number (tLi+ increased by 0.1), and about 4 times higher limiting current density than those recorded for the pure polymer. Such enhancements in the performance suggest a favorable role of nanosized LLZO in a composite polymer electrolyte system

Solid Electrolytes for Fluoride Ion Batteries: Ionic Conductivity in Polycrystalline Tysonite-Type Fluorides

Batteries based on a fluoride shuttle (fluoride ion battery, FIB) can theoretically provide high energy densities and can thus be considered as an interesting alternative to Li-ion batteries. Large improvements are still needed regarding their actual performance, in particular for the ionic conductivity of the solid electrolyte. At the current state of the art, two types of fluoride families can be considered for electrolyte applications: alkaline-earth fluorides having a fluorite-type structure and rare-earth fluorides having a tysonite-type structure. As regard to the latter, high ionic conductivities have been reported for doped LaF₃ single crystals. However, polycrystalline materials would be easier to implement in a FIB due to practical reasons in the cell manufacturing. Hence, we have analyzed in detail the ionic conductivity of La_1–<i>y</i>Ba_<i>y</i>F_3–<i>y</i> (0 ≤ <i>y</i> ≤ 0.15) solid solutions prepared by ball milling. The combination of DC and AC conductivity analyses provides a better understanding of the conduction mechanism in tysonite-type fluorides with a blocking effect of the grain boundaries. Heat treatment of the electrolyte material was performed and leads to an improvement of the ionic conductivity. This confirms the detrimental effect of grain boundaries and opens new route for the development of solid electrolytes for FIB with high ionic conductivities

Nanostructured Fluorite-Type Fluorides As Electrolytes for Fluoride Ion Batteries

Fluoride ion batteries (FIB) provide an interesting alternative to lithium ion batteries, in particular because of their larger theoretical energy densities. These batteries are based on a F anion shuttle between a metal fluoride cathode and a metal anode. One critical component is the electrolyte that should provide fast anion conduction. So far, this is only possible in solid so-called superionic conductors, at elevated temperatures. Herein, we analyze in detail the ionic conductivity in barium fluoride salts doped with lanthanum (Ba_1–<i>x</i>La_<i>x</i>F_2+<i>x</i>). Doping by trivalent cations leads to an increase of the quantity of point defects in the BaF₂ crystal. These defects participate in the ionic motion and therefore improve the ionic conductivity. We demonstrate that further improvement of the conductivity is possible by using a nanostructured material providing additional conduction paths through the grain boundaries. Using electrochemical impedance spectroscopy and AC conductivity analysis, we show that the ionic conduction in this material is controlled by the motion of vacancies through the grain boundaries. The mobility of the vacancies is influenced by the quantity of dopant but decrease for too large dopant concentrations. The optimum compositions having the highest conductivities are Ba_0.6La_0.4F_2.4 and Ba_0.7La_0.3F_2.3. The compound Ba_0.6La_0.4F_2.4 was successfully used as an electrolyte in a FIB

Additive Effects of LiBH₄ and ZrCoH₃ on the Hydrogen Sorption of the Li-Mg-N‑H Hydrogen Storage System

LiBH₄ is an effective catalyst for the hydrogen sorption of the Li-Mg-N-H storage system. A combination of LiBH₄ with ZrCoH₃ was reported to be catalytically more effective. In this work, materials doped with LiBH₄ or ZrCoH₃ or a combination of ZrCoH₃ and LiBH₄ were characterized both in the as-prepared and in the cycled states. A comparison of the metathesis conversion, thermal behavior, kinetics, and phase evolution induced by H₂ cycling suggests that the two components function additively. While LiBH₄ facilitates the metathesis conversion in the first cycle and enhances kinetics during H₂ cycling by forming a quaternary complex hydride, ZrCoH₃ has at least a pulverizing effect in the material. The chemical environment and near order of the individual atoms of Zr and Co as well as the structural parameters of ZrCoH₃ were investigated by X-ray absorption and found to be unchanged during H₂ cycling

Influence of Chloride Ion Substitution on Lithium-Ion Conductivity and Electrochemical Stability in a Dual-Halogen Solid-State Electrolyte

Li+ conducting halide solid-state electrolytes (SEs) are developing as an alternative to contemporary oxide and sulfide SEs for all-solid-state batteries (ASSBs) due to their high ionic conductivity, excellent chemical and electrochemical oxidation stability, and good deformability. However, the instability of halide SEs against the Li anode is still one of the key challenges that need to be addressed. Among halides, fluorides have shown a wider electrochemical stability window due to fluoride’s high electronegativity and smaller ionic radius. However, the ionic conductivity of fluoride-based SEs is lower compared to other halide-based SEs. To achieve better interface stability with the Li anode, the presence of fluoride is not only advantageous for a wider potential window but also forms a stable passivation layer at the Li/SEs interface. Therefore, developing mixed halogen-based solid electrolytes, particularly fluorine and chlorine-based SEs are promising in ASSBs. Herein, we report dual halogen-based SEs, Li2ZrF6–xClx (0 ≤ x ≤ 2), synthesized via ball-milling. The X-ray diffraction results revealed that Li2ZrF6–xClx compounds crystallize in the trigonal phase (P3̅1m). Using impedance spectroscopy, an increase in Li+ conductivity with the increase in Cl content was observed for Li2ZrF6–xClx. Compared with x = 0, Li+ conductivity for the sample with x = 1 improved by ∼5 orders of magnitude. The Li+ conductivities for Li2ZrF5Cl1 at 25 and 100 °C are 5.5 × 10–7 and 2.1 × 10–5 S/cm, respectively. Moreover, Li2ZrF5Cl1 exhibits the widest electrochemical stability window and excellent Li interface stability. Our work indicates Li2ZrF6–xClx as an attractive material for optimization in the class of halide-based solid-state Li-ion conductors