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The performance of all‐solid‐state batteries (ASSBs) relies on the Li+ transport and stability characteristics of solid electrolytes (SEs). Li3PS4 is notable for its stability against lithium metal, yet its ionic conductivity remains a limiting factor. This study leverages local structural disorder via O substitution to achieve an ionic conductivity of 1.38 mS cm−1 with an activation energy of 0.34 eV for Li3PS4−xOx (x = 0.31). Optimal O substitution transforms Li+ transport from 2D to 3D pathways with increased ion mobility. Li3PS3.69O0.31 exhibits improvements in the critical current density and stability against Li metal and retains its electrochemical stability window compared with Li3PS4. The practical implementation of Li3PS3.69O0.31 in ASSBs half‐cells, particularly when coupled with TiS2 as the cathode active material, demonstrates substantially enhanced capacity and rate performance. This work elucidates the utility of introducing local structural disorder to ameliorate SE properties and highlights the benefits of strategically combining the inherent strengths of sulfides and oxides via creating oxysulfide SEs. [ABSTRACT FROM AUTHOR]

The performance of all‐solid‐state batteries (ASSBs) relies on the Li+ transport and stability characteristics of solid electrolytes (SEs). Li3PS4 is notable for its stability against lithium metal, yet its ionic conductivity remains a limiting factor. This study leverages local structural disorder via O substitution to achieve an ionic conductivity of 1.38 mS cm−1 with an activation energy of 0.34 eV for Li3PS4−xOx (x = 0.31). Optimal O substitution transforms Li+ transport from 2D to 3D pathways with increased ion mobility. Li3PS3.69O0.31 exhibits improvements in the critical current density and stability against Li metal and retains its electrochemical stability window compared with Li3PS4. The practical implementation of Li3PS3.69O0.31 in ASSBs half‐cells, particularly when coupled with TiS2 as the cathode active material, demonstrates substantially enhanced capacity and rate performance. This work elucidates the utility of introducing local structural disorder to ameliorate SE properties and highlights the benefits of strategically combining the inherent strengths of sulfides and oxides via creating oxysulfide SEs. [ABSTRACT FROM AUTHOR]

The correlation between lattice chemistry and cation migration in high‐entropy Li+ conductors is not fully understood due to challenges in characterizing anion disorder. To address this issue, argyrodite family of Li+ conductors, which enables structural engineering of the anion lattice, is investigated. Specifically, new argyrodites, Li5.3PS4.3Cl1.7−xBrx (0 ≤ x ≤ 1.7), with varying anion entropy are synthesized and X‐ray diffraction, neutron scattering, and multinuclear high‐resolution solid‐state nuclear magnetic resonance (NMR) are used to determine the resulting structures. Ion and lattice dynamics are determined using variable‐temperature multinuclear NMR relaxometry and maximum entropy method analysis of neutron scattering, aided by constrained ab initio molecular dynamics calculations. 15 atomic configurations of anion arrangements are identified, producing a wide range of local lattice dynamics. High entropy in the lattice structure, composition, and dynamics stabilize otherwise metastable Li‐deficient structures and flatten the energy landscape for cation migration. This resulted in the highest room‐temperature ionic conductivity of 26 mS cm−1 and a low activation energy of 0.155 eV realized in Li5.3PS4.3Cl0.7Br, where anion disorder is maximized. This study sheds light on the complex structure–property relationships of high‐entropy superionic conductors, highlighting the significance of heterogeneity in lattice dynamics. [ABSTRACT FROM AUTHOR]

Lattice oxygen redox yields anomalous capacity and can significantly increase the energy density of layered Li‐rich transition metal oxide cathodes, garnering tremendous interest. However, the mechanism behind O redox in these cathode materials is still under debate, in part due to the challenges in directly observing O and following associated changes upon electrochemical cycling. Here, with 17O NMR as a direct probe of O activities, it is demonstrated that stacking faults enhance O redox participation compared with Li2MnO3 domains without stacking faults. This work is concluded by combining both ex situ and in situ 17O NMR to investigate the evolution of O at 4i, 8j sites from monoclinic C2/m and 6c(1), 6c(2), 6c(3) sites from the stacking faults (P3112). These measurements are further corroborated and explained by first‐principles calculations finding a stabilization effect of stacking faults in delithiated Li2MnO3. In situ 17O NMR tracks O activities with temporal resolution and provides a quantitative determination of reversible O redox versus irreversible processes that form short covalent OO bonds. This work provides valuable insights into the O redox reactions in Li‐excess layered cathodes, which may inspire new material design for cathodes with high specific capacity. [ABSTRACT FROM AUTHOR]

Fast charging (<15 min) of lithium‐ion batteries (LIBs) for electrical vehicles (EVs) is widely seen as the key factor that will greatly stimulate the EV markets, and its realization is mainly hindered by the sluggish diffusion of Li+. To have a mechanistic understanding of Li+ diffusion within LIBs, in this study, structural evolutions of electrodes for a Ni‐rich LiNi0.6Mn0.2Co0.2O2 (NMC622) || graphite cylindrical cell with high areal loading (2.78 mAh cm−2) are developed for operando neutron powder diffraction study at different charging rates. Via sequential Rietveld refinements, changes in structures of NMC622 and LixC6 are obtained during moderate and fast charging (from 0.27 C to 4.4 C). NMC622 exhibits the same structural evolution regardless of C‐rates. For phase transitions of LixC6, the stage I (LiC6) phase emerges earlier during the stepwise intercalation at a lower state of charge when charging rate is increased. It is also found that the stage II (LiC12) → stage I (LiC6) transition is the rate‐limiting step during fast charging. The LiC12 → LiC6 transition mechanism is further analyzed using the Johnson–Mehl–Avrami–Kolmogorov model. It is concluded as a diffusion‐controlled, 1D phase transition with decreasing nucleation kinetics under increasing chargingrates. [ABSTRACT FROM AUTHOR]

LiNiO2 (LNO) represents the end member in the compositional space of the LiNi1‐x‐yMnxCoyO2 (as x and y approach zero) cathode system. Despite its high theoretical specific capacity (275 mAh/g), LNO suffers from phase transitions with large volume change and unfavorable reactions upon electrochemical cycling, which restricts its practical use in the application of lithium‐ion batteries. While the contributing factor to the structural instability is commonly linked to the undesired volume collapse associated with the H2‐H3 phase transition, detailed analysis of structural evolution following the entire route of phase transitions (H1‐M‐H2‐H3) in real time under battery operating conditions remains a challenging task. In this work, we employ operando neutron diffraction to study the structural changes (crystal lattice, Li/Ni−O bond length, O−Ni−O bond angles, and LiO2/NiO2 layer thickness) of LNO cathode in a home‐built LixNiO2||graphite full cell during Li+ de‐/intercalation. In particular, the anomalous increase(decrease) of Ni−O(Li−O) bond length at high SOC (>∼85 %) in the H3 phase is discussed in the context of O2− (2p)→Ni4+(3d) negative charge transfer. [ABSTRACT FROM AUTHOR]

The correlation between lattice chemistry and cation migration in high‐entropy Li+ conductors is not fully understood due to challenges in characterizing anion disorder. To address this issue, argyrodite family of Li+ conductors, which enables structural engineering of the anion lattice, is investigated. Specifically, new argyrodites, Li5.3PS4.3Cl1.7−xBrx (0 ≤ x ≤ 1.7), with varying anion entropy are synthesized and X‐ray diffraction, neutron scattering, and multinuclear high‐resolution solid‐state nuclear magnetic resonance (NMR) are used to determine the resulting structures. Ion and lattice dynamics are determined using variable‐temperature multinuclear NMR relaxometry and maximum entropy method analysis of neutron scattering, aided by constrained ab initio molecular dynamics calculations. 15 atomic configurations of anion arrangements are identified, producing a wide range of local lattice dynamics. High entropy in the lattice structure, composition, and dynamics stabilize otherwise metastable Li‐deficient structures and flatten the energy landscape for cation migration. This resulted in the highest room‐temperature ionic conductivity of 26 mS cm−1 and a low activation energy of 0.155 eV realized in Li5.3PS4.3Cl0.7Br, where anion disorder is maximized. This study sheds light on the complex structure–property relationships of high‐entropy superionic conductors, highlighting the significance of heterogeneity in lattice dynamics. [ABSTRACT FROM AUTHOR]

Lattice oxygen redox yields anomalous capacity and can significantly increase the energy density of layered Li‐rich transition metal oxide cathodes, garnering tremendous interest. However, the mechanism behind O redox in these cathode materials is still under debate, in part due to the challenges in directly observing O and following associated changes upon electrochemical cycling. Here, with 17O NMR as a direct probe of O activities, it is demonstrated that stacking faults enhance O redox participation compared with Li2MnO3 domains without stacking faults. This work is concluded by combining both ex situ and in situ 17O NMR to investigate the evolution of O at 4i, 8j sites from monoclinic C2/m and 6c(1), 6c(2), 6c(3) sites from the stacking faults (P3112). These measurements are further corroborated and explained by first‐principles calculations finding a stabilization effect of stacking faults in delithiated Li2MnO3. In situ 17O NMR tracks O activities with temporal resolution and provides a quantitative determination of reversible O redox versus irreversible processes that form short covalent OO bonds. This work provides valuable insights into the O redox reactions in Li‐excess layered cathodes, which may inspire new material design for cathodes with high specific capacity. [ABSTRACT FROM AUTHOR]

A terbium-based metal-organic framework (MOF) with exceptional water stability for highly selective detection of pesticide thiamethoxam (TMX) in aqueous solution is reported. To date, most reported lanthanide metal-organic frameworks (Ln-MOFs) still exhibit poor water stability, which may limit their practical applications in bio-sensing and detecting pollutants in environmental water samples. In this work, a Tb-MOF [Tb(BDC) 1.5 (DEF)·0.5H 2 O] n (1, BDC = 1,4-benzene dicarboxylate, DEF = N , N -diethylformamide) was prepared by hydrothermal reactions of 1,4-benzenedicarboxylic acid with the corresponding rare earth ions of Tb 3+ . Impressively, water stability surveys of compound 1 indicated that it maintained at least 90% of its emission intensity after storage in water for several months. This characteristic of long water stability is unusual as compared to other Ln-MOFs, making compound 1 an excellent candidate for sensing applications in the aqueous phase. In particular, the green emission of compound 1 could be quenched by the pesticide thiamethoxam (TMX), which was attributed to both the static and dynamic quenching processes based on an upward-curving Stern-Volmer plot. The quenching mechanism was speculatively attributed to the inner filter effect combined with the complex formation based on the electrostatic interaction of compound 1 and TMX, resulting in the promotion of the quenching efficiency. Finally, compound 1 was demonstrated to detect TMX in aqueous solution with rapid response and high selectivity., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)