Dioscorea sativa

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Synthesis, Computed Stability, and Crystal Structure of a New Family of Inorganic Compounds: Carbonophosphates

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Synthesis, Computed Stability, and Crystal Structure of a New Family of Inorganic Compounds: Carbonophosphates

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Synthesis, Computed Stability, and Crystal Structure of a New Family of Inorganic Compounds: Carbonophosphates

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Synthesis, Computed Stability, and Crystal Structure of a New Family of Inorganic Compounds: Carbonophosphates

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Synthesis, Computed Stability, and Crystal Structure of a New Family of Inorganic Compounds: Carbonophosphates

<i>Ab initio</i>-based high-throughput computing and screening are now being used to search and predict new functional materials and novel compounds. However, systematic experimental validation on the predictions remains highly challenging, yet desired. Careful comparison between computational predictions and experimental results is sparse in the literature. Here we report on a systematic experimental validation on previously presented computational predictions of a novel alkali carbonophosphate family of compounds. We report the successful hydrothermal synthesis and structural characterization of multiple sodium carbonophosphates. The experimental conditions for formation of the carbonophosphates and the computational results are compared and discussed. We also demonstrate topotactic chemical de-sodiation of one of the compounds, indicating the potential use of this novel class of compounds as Li⁺ or Na⁺ insertion electrodes

Influence of Stacking on H⁺ Intercalation in Layered <i>A</i>CoO₂ (<i>A</i> = Li, Na) Cathode Materials and Implications for Aqueous Li-Ion Batteries: A First-Principles Investigation

Li- and Na-ion batteries are effective energy storage technologies. Nonetheless, currently used organic-electrolyte batteries present well-known safety problems. Therefore, the research community is intensively looking for potential alternatives. Aqueous batteries based on low-cost salts in water could be an interesting choice since they are safe and environmentally benign. However, working with aqueous electrolytes brings new detrimental mechanisms such as proton intercalation. Understanding the (de)­intercalation chemistry of protons and alkali is one of the keys for designing cathode materials in such aqueous electrochemical cells. In this work, we carry out density functional theory calculations to investigate the H+/alkali exchange in layered LiCoO2 and NaCoO2 materials. By computing the grand potential phase diagram and voltage–composition plots, we determine the relative stability of several orderings of protons, alkali, and vacancies. The fully protonated CoO2 lattice (CoO­(OH)) is revealed to be the most stable insertion product due to the formation of interlayer hydrogen bonds. Our computations demonstrate the key role of layer stacking: H+ insertion is favored in prismatic (P) stacking, while Li favors octahedral (O) stacking. While the fully protonated layered cobalt oxide is the thermodynamically favored product when protons and alkali compete, we show that mixing protons and lithium is energetically disfavored because of the different stacking preferences. We suggest that the kinetic difficulty in nucleating fully protonated phases in the layered oxide prevents proton insertion when cycling LiCoO2 in an aqueous electrolyte. The good cyclability and lack of proton insertion in LiCoO2 are, therefore, a result of the slow kinetics of protonation in partially lithiated cobalt oxide. On the other hand, we demonstrate that NaCoO2 is prone to proton and alkali mixing due to the different stacking preferences for sodium. We hypothesize that this could lead to proton intercalation and poor performances in aqueous batteries for NaCoO2 cathodes

Evaluation of Tavorite-Structured Cathode Materials for Lithium-Ion Batteries Using High-Throughput Computing

Cathode materials with structure similar to the mineral tavorite have shown promise for use in lithium-ion batteries, but this class of materials is relatively unexplored. We use high-throughput density-functional-theory calculations to evaluate tavorite-structured oxyphosphates, fluorophosphates, oxysulfates, and fluorosulfates for use as cathode materials in lithium-ion batteries. For each material we consider the insertion of both one and two lithium ions per redox-active metal, calculating average voltages and stability relative to a database of nearly 100,000 previously calculated compounds. To evaluate lithium mobility, we calculate the activation energies for lithium diffusion through the known tavorite cathode materials LiVO(PO4), LiV(PO4)F, and LiFe(SO4)F. Our calculations indicate that tavorite-structured materials are capable of very high rates of one-dimensional lithium diffusion, and several tavorite-structured materials may be capable of reversibly inserting two lithium ions per redox-active metal

Effect of Aqueous Electrolytes on LiCoO₂ Surfaces: Role of Proton Adsorption on Oxygen Vacancy Formation

Aqueous electrolytes are a safer, greener, and cheaper solution for energy storage applications. However, aqueous Li-ion batteries (ALIBs) suffer from faster degradation and poorer cyclability. The presence of H+ and O loss have often been claimed to deteriorate electrode materials in aqueous electrolytes. Understanding the surface reactivity of the commercial LiCoO2 cathode with respect to aqueous electrolytes and O loss is essential for designing cathode materials in such aqueous electrochemical cells. In this work, we use density functional theory calculations to investigate the stability and structure of several low-index surfaces of layered Li1–xCoO2 (0 ≤ x ≤ 0.5) before and after H+ adsorption. We compute the binding energies of H+ from low to full coverage regimes. By employing ab initio atomistic thermodynamics, we determine the stability of O vacancies on protonated and nonprotonated layered LiCoO2 surfaces. Our computations demonstrate that O loss is energetically favorable on the lowest energy surfaces, i.e., on the most exposed surface terminations. We suggest that the O vacancy formation is directly related to the transition metal (Co) coordination. Finally, the role of H+ on O loss is investigated, showing that H+ can facilitate the generation of O vacancies in some surface terminations

Evaluation of Tavorite-Structured Cathode Materials for Lithium-Ion Batteries Using High-Throughput Computing

Cathode materials with structure similar to the mineral tavorite have shown promise for use in lithium-ion batteries, but this class of materials is relatively unexplored. We use high-throughput density-functional-theory calculations to evaluate tavorite-structured oxyphosphates, fluorophosphates, oxysulfates, and fluorosulfates for use as cathode materials in lithium-ion batteries. For each material we consider the insertion of both one and two lithium ions per redox-active metal, calculating average voltages and stability relative to a database of nearly 100,000 previously calculated compounds. To evaluate lithium mobility, we calculate the activation energies for lithium diffusion through the known tavorite cathode materials LiVO(PO4), LiV(PO4)F, and LiFe(SO4)F. Our calculations indicate that tavorite-structured materials are capable of very high rates of one-dimensional lithium diffusion, and several tavorite-structured materials may be capable of reversibly inserting two lithium ions per redox-active metal