van der Waals Interactions in Layered Lithium Cobalt Oxides

The role of van der Waals (vdW) interactions in density functional theory (DFT) + <i>U</i> calculations of the layered lithium-ion battery cathode Li_<i>x</i>CoO₂ (<i>x</i> = 0–1) is investigated using (i) dispersion corrections in the Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation functional, (ii) vdW density functionals, and (iii) the Bayesian error estimation functional with vdW correlation. We find that combining vdW corrections or functionals with DFT+<i>U</i> can yield lithiation voltages, relative stabilities, and structural properties that are in much better agreement with experiments for the phases O1-CoO₂, O3-CoO₂, layered-Li_0.5CoO₂, spinel-Li_0.5CoO₂, and LiCoO₂ than using DFT+<i>U</i> or vdW-inclusive methods alone or using the hybrid Heyd–Scuseria–Ernzerhof functional. Contributions of vdW interactions to the lithiation voltages are estimated to have a similar magnitude with that of applying a typical <i>U</i> in the range 2–4 eV for cobalt, each accounting for 5–10% of calculated voltages relative to PBE. Relative stabilities of O1 and O3-CoO₂ as well as layered- and spinel-Li_0.5CoO₂ are correctly predicted with vdW-inclusive methods combined with the +<i>U</i> correction

Controlling the Intercalation Chemistry to Design High-Performance Dual-Salt Hybrid Rechargeable Batteries

We have conducted extensive theoretical and experimental investigations to unravel the origin of the electrochemical properties of hybrid Mg²⁺/Li⁺ rechargeable batteries at the atomistic and macroscopic levels. By revealing the thermodynamics of Mg²⁺ and Li⁺ co-insertion into the Mo₆S₈ cathode host using density functional theory calculations, we show that there is a threshold Li⁺ activity for the pristine Mo₆S₈ cathode to prefer lithiation instead of magnesiation. By precisely controlling the insertion chemistry using a dual-salt electrolyte, we have enabled ultrafast discharge of our battery by achieving 93.6% capacity retention at 20 C and 87.5% at 30 C, respectively, at room temperature

Additional file 2: of Prospective observations study protocol to investigate cost-effectiveness of various prenatal test strategies after the introduction of noninvasive prenatal testing

Physicians Questionnaire: Korean version and Physicians Questionnaire: English version. (ZIP 536 kb

First-Principles Study of Lithium Cobalt Spinel Oxides: Correlating Structure and Electrochemistry

Embedding a lithiated cobalt oxide spinel (Li₂Co₂O₄, or LiCoO₂) component or a nickel-substituted LiCo_1–<i>x</i>Ni_<i>x</i>O₂ analogue in structurally integrated cathodes such as <i>x</i>Li₂MnO₃·(1–<i>x</i>)­LiM′O₂ (M′ = Ni/Co/Mn) has been recently proposed as an approach to advance the performance of lithium-ion batteries. Here, we first revisit the phase stability and electrochemical performance of LiCoO₂ synthesized at different temperatures using density functional theory calculations. Consistent with previous studies, we find that the occurrence of low- and high-temperature structures (i.e., cubic lithiated spinel LT-LiCoO₂; or Li₂Co₂O₄ (<i>Fd</i>3̅<i>m</i>) vs trigonal-layered HT-LiCoO₂ (<i>R</i>3̅<i>m</i>), respectively) can be explained by a small difference in the free energy between these two compounds. Additionally, the observed voltage profile of a Li/LiCoO₂ cell for both cubic and trigonal phases of LiCoO₂, as well as the migration barrier for lithium diffusion from an octahedral (O_h) site to a tetrahedral site (T_d) in <i>Fd</i>3̅<i>m</i> LT-Li_1–<i>x</i>CoO₂, has been calculated to help understand the complex electrochemical charge/discharge processes. A search of LiCo_<i>x</i>M_1–<i>x</i>O₂ lithiated spinel (M = Ni or Mn) structures and compositions is conducted to extend the exploration of the chemical space of Li–Co–Mn–Ni–O electrode materials. We predict a new lithiated spinel material, LiNi_0.8125Co_0.1875O₂ (<i>Fd</i>3̅<i>m</i>), with a composition close to that of commercial, layered LiNi_0.8Co_0.15Al_0.05O₂, which may have the potential for exploitation in structurally integrated, layered spinel cathodes for next-generation lithium-ion batteries

Additional file 1: of Prospective observations study protocol to investigate cost-effectiveness of various prenatal test strategies after the introduction of noninvasive prenatal testing

Patients Questionnaire: Korean version and Patients Quesionnaire: English version. (ZIP 524 kb

Additional file 1: Figure S1. of Prognostic implications of PD-L1 expression in patients with soft tissue sarcoma

Survival analyses according to PD-L1 expression in patients with localized disease. (A) Kaplan-Meier survival curves for recurrence-free survival (RFS). (B) Kaplan-Meier survival curves for overall survival (OS). (TIF 84 kb

Salvia hayatana Makino

原著和名: ヤンバルタムラサウ科名: シソ科 = Labiatae採集地: 台湾 太魯閤〜天祥 (台湾省 太魯閤〜天祥)採集日: 1968/3/14採集者: 萩庭丈壽整理番号: JH048421国立科学博物館整理番号: TNS-VS-99842

Comprehensive Enhancement of Nanostructured Lithium-Ion Battery Cathode Materials via Conformal Graphene Dispersion

Efficient energy storage systems based on lithium-ion batteries represent a critical technology across many sectors including consumer electronics, electrified transportation, and a smart grid accommodating intermittent renewable energy sources. Nanostructured electrode materials present compelling opportunities for high-performance lithium-ion batteries, but inherent problems related to the high surface area to volume ratios at the nanometer-scale have impeded their adoption for commercial applications. Here, we demonstrate a materials and processing platform that realizes high-performance nanostructured lithium manganese oxide (nano-LMO) spinel cathodes with conformal graphene coatings as a conductive additive. The resulting nanostructured composite cathodes concurrently resolve multiple problems that have plagued nanoparticle-based lithium-ion battery electrodes including low packing density, high additive content, and poor cycling stability. Moreover, this strategy enhances the intrinsic advantages of nano-LMO, resulting in extraordinary rate capability and low temperature performance. With 75% capacity retention at a 20C cycling rate at room temperature and nearly full capacity retention at −20 °C, this work advances lithium-ion battery technology into unprecedented regimes of operation