Latest ArticlesPoly(ethylene oxide)-based polymer all-solid-state lithium-sulfur batteries (ASSLSBs) have been a prominent direction in new generation of energy storage devices due to their safety, low cost and high specific energy. However, the performance degradation arising from the “shuttle effect” and poor ion transport dynamics limit its further development. Herein, for the first time, we introduce the concepts of adsorption and catalysis into polymer ASSLSBs. By combining S@KB with g-C3N4, the polysulfides shuttling is significantly inhibited. Meanwhile, the kinetic process of the cathode is obviously improved, which is confirmed by in situ electrochemical impedance spectroscopy. The battery with g-C3N4 can provide a high reversible capacity 1078.5 mAh/g, and can be stabilized for 150 cycles with a final Coulombic efficiency of 97.47%, implying a superior electrochemical stability than previously reported. Furthermore, the intrinsic mechanisms of adsorption and catalysis are intensively studied by means of XPS, DFT calculations, and galvanostatic intermittent titration technique. Changes in electrode properties before and after cycling have also been used to study battery stability. Overall, this work will open the door to the novel polymer all-solid-state lithium-sulfur battery design for practical realization of high-energy batteries.
Argyrodite-based all-solid-state batteries exhibit significant potential as energy storage devices across a wide temperature zone. The Li-ion and electronic conductivities in the cathode mixture is crucial factor in determining the corresponding electrochemical performances. Here, an effective charge carrier distribution is tailored by introducing Li3InCl6 electrolyte with wider voltage stability surrounding the bare LiNi0.7Co0.2Mn0.1O2 to promote ionic conductivity and mixing carbon additives to enhance electronic conductivity. The Li3InCl6@LiNi0.7Co0.2Mn0.1O2/Li5.5PS4.5Cl1.5/Li-In battery exhibits superior electrochemical performance at various C-rates over a wide operating temperature range due to the enhanced charge carrier conducting rates. It delivers high charge/discharge capacities, superior rate capability and exceptional cycling performance. Specifically, the battery delivers initial discharge capacities of 202 mAh/g at 0.2 C and retains a discharge capacity of 162 mAh/g at 2 C with a capacity retention of 91.8% over 500 cycles when cycled at room temperature. Moreover, due to the Li3InCl6 coating layer and the carbon additive in the cathode, it exhibits higher discharge capacities and superior cycling performances when operated at -20 and 60 ℃. This work presents a guideline for fabricating high-performance all-climate solid-state lithium batteries via tailoring the charger carriers conducting pathway in the electrode structure.
The quest for sustainable and efficient energy storage solutions has led to significant advancements in the field of solid-state batteries, with a particular focus on solid-state electrolytes (SSEs) especially highly ionic conductive sulfide and halide materials. However, the air instability of these SSEs not only limits their mass production but also poses environmental and safety risks. Herein, the damage of humid-air exposure on the structure and electrochemical properties of Li5.5PS4.5Cl0.8Br0.7 and Li3InCl6 is evaluated, and a subsequent heat treatment is proposed and proven effective to recover the damage, whose mechanisms are pinpointed through XRD data with Retvield refinement. For the exposed samples, a lattice contraction occurs as the hydrolysis reaction caused by H2O from humid air severely damages the structure, which impedes lithium-ion transport. After heat treatment, a lattice rearrangement can rebuild sufficient lithium-ion pathway in the material, leading to the greatly improved ionic conductivity. As a result, the treated electrolytes provide greatly promoted ionic conductivity (from 0.95 mS/cm to 1.8 mS/cm for Li3InCl6, from 1.24 S/cm to 7.04 S/cm for Li5.5PS4.5Cl0.8Br0.7). More importantly, ASSBs employed with the treated electrolytes achieve outstanding long-term cycling and rate performance, even guarantee considerable capacity output of ~217 and ~159 mAh/g under extreme conditions of 60 and –20 ℃, illustrating significantly improved electrochemical reaction kinetics and the impressive reliability of the heat treatment method.
The disordered structure plays an essential role in high capacity of hard carbon. However, the lack of universal descriptor for characterizing the structural disorder of hard carbon limit advancements in understanding and optimizing its sodium diffusion performance in sodium ion batteries (SIBs). Herein, fractal dimension (D) revealed by small angle X-ray scattering (SAXS) is identified as a descriptor of hard carbon’s structural disorder under the data-driven methods, correlating it with electrochemical and structural features. Porod’s law, TEM and XRD are used to determine the correlation between D and the microstructure of hard carbon. The results reveal that as D increases, pseudo-graphitic domains decrease and carbon layers become more curved, which result in more closed pores. Meanwhile, the diffusion coefficient in different potential below 0.1 V vs. Na+/Na suggest that D are unfavorable to sodium ions diffusion as the diffusion coefficients decrease with D increase and result in a reduce of slope capacity percentage in SIBs. D are used in analyze the sodium ion storage behavior by ex-situ SAXS, which suggests that carbon layers with larger D have more structural defects as nucleation sites. In addition, theoretical plateau capacity utilization (TCU) is proposed based on D and reveal the accessibility of closed pore of hard carbon. This work provides a foundation for bridging the gap between structural characterization and practical performances, and guiding the structural design of hard carbon with high sodium storage and kinetic performance.
Silicon/graphite (Si/C) composites, which combine the advantages of Si anodes and commercial graphite anodes, are promising anode materials for high-energy-density lithium-ion batteries (LIBs). Despite experimental and theoretical studies on the electrochemical characteristics of different silicon crystal surfaces, there have been limited investigations on the electrochemical and mechanical properties of Si composite anode materials with different graphite crystal planes, such as the electrode interfaces between Si(111) and graphite (0001), as well as amorphous Si and graphite (1010). In this study, models of Si/C anode interfaces for LIBs were constructed to explore the mechanical-electrochemical-low-temperature performance by density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The calculation results indicate that upon Li intercalation into the graphite (1010) surface, the electrical conductivity, electrochemical adsorption, and interfacial mechanical strength of the Si/C composite are significantly enhanced, with a separation work that is 2.3 times higher than that of Si/C on the graphite (0001) surface. More importantly, AIMD simulations at low temperatures reveal that the interface between graphite (1010) and amorphous Si forms a solid electrolyte interphase (SEI) rich in organic components, which significantly improves the Li-diffusion kinetics. This discovery provides new insights for the design and optimization of Si/C anode materials for low-temperature LIBs.
The oxidative coupling reaction of methane (OCM) process offers a promising pathway for the direct conversion of methane into high value C2 hydrocarbons (C2H6 and C2H4), albeit facing the challenges of harsh reaction conditions and competing overoxidation reaction. Herein, Ba-doped Eu2O3 synthesized via the spray pyrolysis method was employed as highly active dopant catalyst for the methane oxidative coupling reaction. The prepared Eu0.9Ba0.1Ox catalyst showed satisfactory reactivity and stability, with a C2+ product selectivity of 52.4%, a C2+ yield of 16.2%, and a stabilization time of at least 100 h. The incorporation of Ba atoms into Eu2O3 lattice leads to an increased molar ratio of Eu2+/Eu3+ and a higher oxygen vacancies (Ov) concentration. Such modulation of surface electronic state significantly improves the adsorption and activation behavior of oxygen, thereby accelerating the production of reactive oxygen species (O2−). Meanwhile, the acid-base properties of Eu2O3 substrate also undergo obvious alteration with more basic site generation after Ba doping, which is conducive to the stabilization activated oxygen. O2− substances can promote the activation of methane into methyl radicals, and also facilitate the dehydrogenation of ethane into ethylene, thus improving the catalytic activity.
Hard carbon with abundant resources and superior sodium storage performance is the most representative anode material for sodium-ion batteries (SIBs), but suffers from unsatisfied reversible capacity and low initial Coulombic efficiency. Herein, brown coal is employed as the precursor to obtain high-performance hard carbon anode materials with the assistance of pre-oxidation treatment for SIBs. The unique pre-oxidation treatment introduces an abundance of oxygen-containing functional groups to regulate the microstructure of hard carbon anode, achieving a more disordered phase structure for improved sodium storage performance. These enable a high reversible specific capacity of 316.1 mAh/g with an initial Coulombic efficiency of 87.6%, significantly higher than those of 236.5 mAh/g and 71.7% in carbonized pristine brown coal. Meanwhile, the adsorption-insertion-pore filling sodium storage mechanism of brown coal-derived hard carbon is demonstrated by in-situ XRD and Raman. This work emphasizes the role of pre-oxidation treatment on boosting the sodium storage performance of brown coal-derived hard carbon for advanced SIBs.
The combination of high-nickel cathodes with poly(ethylene oxide) (PEO)-based solid-state electrolytes represents a promising strategy to achieve both high energy density and enhanced safety. However, existing studies predominantly employ LiFePO4 cathodes due to the inherent limitations of PEO-based electrolytes in high-voltage stability. Even with the improved electrochemical stability window (ESW) of PEO-based electrolytes, current implementations still utilize low-nickel-content (≤80%) cathodes. To further enhance the energy density of PEO-based solid-state batteries (SSBs), this work employs high-nickel-content (> 80%) cathodes in conjunction with PEO-based electrolytes. The influence of nickel content in cathode materials (CAMs) on the electrochemical performance of PEO-based SSBs is systematically investigated through a progressive nickel content optimization approach. This study elucidates the intrinsic relationship between the nickel content and the characteristic capacity activation mechanism observed during the initial cycling phases in solid-state battery systems, revealing a nickel-content-dependent electrochemical activation pattern unique to solid-state configurations. Additionally, through a series of detection schemes, the failure mechanism of high-nickel PEO-based SSBs is systematically studied from the cathode/electrolyte interface, electrolyte, and CAM. Particularly, the degree of PEO decomposition is quantitatively analyzed using differential electrochemical mass spectrometry (DEMS) and gel permeation chromatography (GPC). This work reveals the key issues faced when further increasing the nickel content of CAMs, providing insights for targeted modification designs of high-nickel PEO-based solid-state batteries in the future.
Upconversion nanoparticles (UCNPs) have been naturally entangled with surface phonons since their discovery due to their high specific surface area. However, in addition to quenching luminescence at ambient temperatures, surface phonons play a crucial role in activating the dark layer between the sensitizer and the activator to enhance luminescence in thermal environments. Considering that the positive effect of surface phonons may be eliminated under inert cladding, a β-NaGdF4:Yb,Tm@NaYF4@NaGdF4:Yb,Er core-shell-shell upconversion luminescence (UCL) system with two opposite thermo-responsive luminescence behaviors is designed here. The imposition of an inert intermediate shell layer causes the weakening of the blue luminescence of the core Tm ions in the thermal environment, while on the contrary the outermost Er ions realize an effective enhancement of luminescence with the help of surface phonons. In addition, the photoluminescence results show that effective modulation of luminescence color can be achieved by changing the thickness of the inert shell layer, the concentration of Er ions in the activation layer, and the excitation power. Finally, the distinct thermally responsive luminescence behaviors and temperature-dependent color variations enabled moderate temperature sensing and information encryption applications. The maximum relative and absolute sensitivities can be up to 1.62%/K and 0.64%/K from 298 K to 573 K, respectively. These findings provided new insights into optimizing the luminescent properties of fluorides and provided a new platform for the application of multiple properties in a material.
Chiral hybrid metal halides, known for their exceptional piezoelectric properties, facile synthesis, and design flexibility, have become promising candidates for advanced piezoelectric devices. However, most chiral metal halides contain toxic lead and are predominantly restricted to 1D or 2D structures. In contrast, 0D hybrid piezoelectric materials, despite their lower elastic moduli, remain significantly less explored. Here, we report the synthesis of a pair of lead-free chiral 0D hybrid metal halides, R-(APP)2CoBr4 and S-(APP)2CoBr4 (APP = 2-amino-3-phenylpropan-1-ol). First-principles calculations reveal that S-(APP)2CoBr4 exhibits a noticeable shear piezoelectric coefficient while maintaining a relatively low elastic modulus. Furthermore, S-(APP)2CoBr4/PDMS composite films (PDMS = polydimethylsiloxane) were fabricated and their potential for energy harvesting and human motion sensing was investigated. Under a 2 N applied force, a 15 wt% S-(APP)2CoBr4/PDMS composite film exhibits promising performance, generating an open-circuit voltage of 10.21 V and a short-circuit current of 1.02 µA. Additionally, the low acoustic impedance of S-(APP)2CoBr4 (5.80–6.67 MRayl) and its compatibility with water (1.5 MRayl) facilitate efficient ultrasound transmission in composite devices, ensuring precise localization of ultrasound sources. These findings offer valuable insights into the potential of lead-free 0D hybrid metal halides for advanced electromechanical applications.
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