Capacity fading has limited commercial layered Li-ion battery electrodes to <70% of their theoretical capacity. Higher capacities can be achieved initially by charging to higher voltages, however, ...these gains are eroded by a faster fade in capacity. Increasing lifetimes and reversible capacity are contingent on identifying the origin of this capacity fade to inform electrode design and synthesis. We used operando X-ray diffraction to observe how the lithiation-delithiation reactions within a LiNi0.8Co0.15Al0.05O2 (NCA) electrode change after capacity fade following months of slow charge–discharge. The changes in the reactions that underpin energy storage after long-term cycling directly correlate to the capacity loss; heterogeneous reaction kinetics observed during extended cycles quantitatively account for the capacity loss. This reaction heterogeneity is ultimately attributed to intergranular fracturing that degrades the connectivity of subsurface grains within the polycrystalline NCA aggregate.
The kinetics and uniformity of ion insertion reactions at the solid-liquid interface govern the rate capability and lifetime, respectively, of electrochemical devices such as Li-ion batteries. Using ...an operando x-ray microscopy platform that maps the dynamics of the Li composition and insertion rate in LixFePO₄, we found that nanoscale spatial variations in rate and in composition control the lithiation pathway at the subparticle length scale. Specifically, spatial variations in the insertion rate constant lead to the formation of nonuniform domains, and the composition dependence of the rate constant amplifies nonuniformities during delithiation but suppresses them during lithiation, and moreover stabilizes the solid solution during lithiation. This coupling of lithium composition and surface reaction rates controls the kinetics and uniformity during electrochemical ion insertion.
An all‐solid‐state lithium battery based on a sulfide electrolyte is one of the most promising next‐generation energy storage systems. However, the high interfacial impedance, particularly due to the ...internal pores in the electrode or electrolyte layers, is the major limiting factor to the development of sheet‐type all‐solid‐state batteries. In this study, a low‐resistance integrated all‐solid composite electrode is developed using a hybrid of a pyrrolidinium‐based ionic liquid and a polyethylene oxide polymer with lithium salt as a multifunctional interphase material, which is engineered to be compatible with the sulfide electrolyte as well as the fabrication process of sheet‐type composite electrode. The interphase material fills the pore in the composite sheet while binding the components together, which effectively increases the interfacial contact area and strengthens the physical network between the components, thereby enabling enhanced ion transport throughout the electrode. The interphase‐engineered sheet‐type LiNi0.8Co0.1Mn0.1O2 /Li10GeP2S12 electrode shows a high reversible capacity of 166 mAh g−1 at 25 °C, corresponding to 92% of the observed capacity in a current liquid‐based cathode system, as well as enhanced cycle and rate performances. This study proposes a novel and practical method for the development of high‐performance sheet‐type all‐solid‐state lithium batteries.
An interphase‐engineered sheet‐type LiNi0.8Co0.1Mn0.1O2/Li10GeP2S12 electrode is developed by applying a hybrid of PEO‐Pyr14TFSI‐LiTFSI as a multifunctional interphase material to be compatible with the sulfide electrolyte. It shows a high reversible capacity (92% utilization) with excellent cycling performance at 25 °C. This study provides a practical method for the development of intrinsically safe and high‐performance all‐solid‐state lithium batteries.
Layered oxides widely used as lithium-ion battery electrodes are designed to be cycled under conditions that avoid phase transitions. Although the desired single-phase composition ranges are well ...established near equilibrium, operando diffraction studies on many-particle porous electrodes have suggested phase separation during delithiation. Notably, the separation is not always observed, and never during lithiation. These anomalies have been attributed to irreversible processes during the first delithiation or reversible concentration-dependent diffusion. However, these explanations are not consistent with all experimental observations such as rate and path dependencies and particle-by-particle lithium concentration changes. Here, we show that the apparent phase separation is a dynamical artefact occurring in a many-particle system driven by autocatalytic electrochemical reactions, that is, an interfacial exchange current that increases with the extent of delithiation. We experimentally validate this population-dynamics model using the single-phase material Li
(Ni
Mn
Co
)O
(0.5 < x < 1) and demonstrate generality with other transition-metal compositions. Operando diffraction and nanoscale oxidation-state mapping unambiguously prove that this fictitious phase separation is a repeatable non-equilibrium effect. We quantitatively confirm the theory with multiple-datastream-driven model extraction. More generally, our study experimentally demonstrates the control of ensemble stability by electro-autocatalysis, highlighting the importance of population dynamics in battery electrodes (even non-phase-separating ones).
Sodium ion batteries, because of their sustainability attributes, could be an attractive alternative to Li-ion technology for specific applications. However, it remains challenging to design high ...energy density and moisture stable Na-based positive electrodes. Here, we report an O3-type NaLi
Mn
O
phase showing anionic redox activity, obtained through a ceramic process by carefully adjusting synthesis conditions and stoichiometry. This phase shows a sustained reversible capacity of 190 mAh g
that is rooted in cumulative oxygen and manganese redox processes as deduced by combined spectroscopy techniques. Unlike many other anionic redox layered oxides so far reported, O3-NaLi
Mn
O
electrodes do not show discernible voltage fade on cycling. This finding, rationalized by density functional theory, sheds light on the role of inter- versus intralayer 3d cationic migration in ruling voltage fade in anionic redox electrodes. Another practical asset of this material stems from its moisture stability, hence facilitating its handling and electrode processing. Overall, this work offers future directions towards designing highly performing sodium electrodes for advanced Na-ion batteries.
•This study constructs an analytic framework to examine the essence and effects of affective atmosphere.•This study demonstrates how affective dynamics are converged to reinforce Taiwanese ...nationalism.•Investigation into how affective nationalism can be employed by the government to dominate public emotions and actions.•This study raises significant concerns regarding the potential risks of emerging ‘surveillance nationalism’.
This article primarily explores the generation and circulation of the affective atmosphere during the COVID-19 crisis, providing a nuanced understanding of the emergence of affective governance. It constructs an analytical framework to examine the spatiality, collectivity, and authority within affective atmospheres, which are essentially interrelated and mutually influential. It argues that the affective atmosphere can be manipulated to direct public emotions and actions, shaping specific forms of affective governance. Through a case study of Taiwan’s response to the COVID-19 pandemic, this paper unfolds how affective dynamics converge to reinforce Taiwanese nationalism through the construction of atmospheric walls, social and psychological mobilisation, and technology-based interventions. It demonstrates that governments adapt to changing atmospheres and achieve their strategic intentions through performative spatial arrangements, emotional appeals and affective rhetoric, as well as the development of a digital surveillance landscape. It illuminates how these epidemic transmission control strategies have driven a shift in governance models towards greater emphasis on transforming and manipulating affective nationalism to stimulate public sentiments and collective actions. Finally, this paper suggests that further research and discussion is needed regarding the multifaceted nature of affective atmospheres to enhance the effectiveness and efficiency of governance mechanisms, as well as to promote civic engagement and inclusivity.
As low‐dimensional lead‐free hybrids with higher stability and lower toxicity than those of three‐dimensional lead perovskites, organic antimony(III) halides show great application potential in ...opt‐electronic field owing to diverse topologies along with exceptional optical properties. We report herein an antimony(III) hybrid (MePPh3)2SbCl5 with a zero‐dimensional (0D) structure, which exhibits brilliant orange emission peaked at 593 nm with near‐unity photoluminescent quantum yield (99.4 %). The characterization of photophysical properties demonstrates that the broadband emission with a microsecond lifetime (3.24 μs) arises from self‐trapped emission (STE). Electrically driven organic light‐emitting diodes (OLEDs) based on neat and doped films of (MePPh3)2SbCl5 were fabricated. The doped devices show significant improvement in comparison to non‐doped OLEDs. Owing to the much improved surface morphology and balanced carrier transport in light‐emitting layers of doped devices, the peak luminance, current efficiency (CE) and external quantum efficiency (EQE) are boosted from 82 cd m−2 to 3500 cd m−2, 1.1 cd A−1 to 6.8 cd A−1, and 0.7 % to 3.1 % relative to non‐doped devices, respectively.
A highly luminescent organic antimony(III) hybrid (MePPh3)2SbCl5 featured with STE emission is prepared with good reproducibility and high stability. High‐efficiency OLEDs are demonstrated with this hybrid as an emitter with the luminance of 3500 cd m−2, current efficiency of 6.8 cd A−1 and EQE of 3.1 %, respectively.
The Fabry–Perot (FP) resonator is an intuitive and versatile optical structure owing to its uniqueness in light‐matter interactions, yielding resonance with a wide range of wavelengths as it couples ...with photonic materials encapsulated in a dielectric cavity. Leveraging the FP resonator for molecular detection, a simple geometry of the metal‐dielectric‐metal structure is demonstrated to allow tuning of the enhancement factors (EFs) of surface‐enhanced Raman scattering (SERS). The optimum near‐field EF from randomly dispersed gold nano‐gaps and dynamic modulation of the far‐field SERS EF by varying the optical resonance of the FP etalon are systematically investigated by performing computational and experimental analyses. The proposed strategy of combining plasmonic nanostructures with FP etalons clearly reveals wavelength matching of FP resonance to excitation and scattering wavelengths plays a key role in determining the magnitude of the SERS EF. Finally, the optimum near‐field generating optical structure with controlled dielectric cavity is suggested for a tunable SERS platform, and its dynamic SERS switching performance is confirmed by demonstrating information encryption through liquid immersion.
Thin metal‐dielectric‐metal structures consisting of Au nanoperforated films utilize Fabry–Perot interference and liquid permeability for tunable surface‐enhanced Raman spectroscopy (SERS). The dielectric layer is etched to boost its SERS signal, and ethanol immersion enables dynamic SERS switching for functional applications. The tunability and scalability of the proposed universal SERS platform demonstrate multiple‐information encryption.
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