Understanding and manipulating the interplay between lattice oxygen redox and interfacial stability is critical for realizing the full potential of lithium-rich manganese-based oxide positive electrodes in all-solid-state lithium batteries. Herein, we comprehensively investigate interfacial evolution of Li-rich manganese-based positive electrodes in sulfide electrolyte (Li6PS5Cl) systems and report that a potential mechanism where irreversible lattice oxygen redox at high potential induces severe electrolyte decomposition, forming porous oxygenated by-products that dominate interfacial impedance and hinder anionic redox reactions. Discharge-driven reduction of these by-products-particularly between 2.6-2.0 V-could facilitates interphases reconstruction via lithium incorporation, enhancing ionic transport kinetics and enabling reversible oxygen redox. Building on this identified mechanism, we propose a pre-activation strategy (3.9-2.0 V pre-cycling) with oxygen-modified Li6PS5Cl, which accelerates interphases stabilization and enables high oxygen redox utilization during the first cycle. It delivers a specific capacity of 318 mAh g-1 at 10 mA g-1, and 226 mAh g-1 at 200 mA g-1 with 83.2% retention over 500 cycles at 60 °C. This work has the potential to provide an effective interfacial reconstruction strategy to enhance anionic redox reversibility, providing a design framework for high-energy lithium-rich positive electrodes in all-solid-state lithium batteries.

With the growing demand for safe and sustainable lithium-ion batteries, there remains a need for alternative anode materials capable of combining high capacity, long-term durability, and low-cost industrial scalability. Herein, nitrogen-doped carbon anodes were directly synthesized from low-ash fat coking coal without ash removal via a medium-temperature carbonization strategy, offering a sustainable and resource-efficient route for carbon anode production. Benefiting from semi-graphitic microdomains, refined pore architecture, enlarged interlayer spacing, and defect-rich nitrogen sites, the optimized Jinda/PVP21 anode delivered a reversible capacity of 305.6 mAh g(-1) at 0.1 A g(-1), excellent rate performance, and sequential long-term cycling durability across 1500 cycles at 0.1, 0.2, and 0.5 A g(-1). More notably, full-cell testing (LiFePO4 vertical bar vertical bar Jinda/PVP21) using a gel polymer electrolyte exhibited an energy density of 282.1 Wh kg(-1) with 80% capacity retention after 500 cycles, demonstrating strong feasibility toward semi-solid-state lithium-ion batteries (LIBs). This work highlights fat coking coal with moderate mineral content and without the need for additional acid leaching or strong alkali treatment, as a viable industrial precursor for heteroatom-doped carbon anodes and provides a scalable platform for future high-performance LIB technologies.

Increasing the upper cut-off voltage of O3-type layered LiCoO2 cathodes is a promising strategy to enhance their specific energy density, attracting significant recent attention. However, this approach induces severe surface reconstruction and poor cycling performance as a result of oxygen loss. To overcome this limitation, we propose a novel synthesis strategy that employs a metastable O2-type LiCoO2 framework combined with a minor Li-defective T2-type Li1-xCoO2 phase, which is transformed via thermal treatment into a stable O3-type LiCoO2 capable of high-voltage operation up to 4.6 V. Surprisingly, this thermal treatment results in the formation of a thin, uniform spinel LiCo2O4 layer on the O3-type LiCoO2 surface. This Li-ion conductive surface layer not only facilitates Li-ion transport but also inhibits structural collapse along the c-axis during high-voltage cycling. Furthermore, it effectively mitigates oxygen loss from the LiCoO2 cathode during long-term cycling. Consequently, the modified O3-type LiCoO2 cathode exhibits a high-capacity retention of 88% at 1 C over 200 cycles (3.0-4.6 V), substantially outperforming its unmodified counterpart (39%). This strategy of converting Li-poor metastable phases into a thermodynamically stable layered structure with a self-formed protective surface layer opens a new avenue for developing high-capacity, stable layered cathodes for advanced lithium-ion batteries.

Mullite-type SmMn2O5-delta exhibits low thermal expansion, but its conductivity and catalytic activity are insufficient for high-performance solid oxide fuel cell cathodes. In this work, Sm is partially substituted by Pr, modulating the conductivity and oxygen-vacancy concentration, to enhance the catalytic activity. At 800 degrees C, the optimal Sm0.5Pr0.5Mn2O5-delta demonstrates a threefold enhancement in electrical conductivity (0.234 S cm(-1)) and a 64% reduction in polarization resistance (0.33 Omega cm(2)) compared to the undoped sample. The Sm0.5Pr0.5Mn2O5-delta-based cell delivers a peak power density of 961 mW cm(-2) at 800 degrees C, with a degradation rate of similar to 6.96% kh(-1) over 450 h of operation. After 50 thermal cycles between 200 and 800 degrees C, the performance degrades by only 0.227%/cycle. These results demonstrate that Pr-doped SmMn2O5-delta significantly enhances electrical conductivity and oxygen reduction reaction catalytic activity while preserving the mullite framework, providing a promising cathode candidate for SOFC with high power output and excellent long-term stability.

The demand for high energy density in the field of Li-ion batteries has intensified interest in lithium-rich Mn-based layered oxide cathodes (LRLOs) owing to their high capacity and low cost. Nevertheless, the thermal runaway becomes an urgent concern because of the high-voltage operation (up to 4.8 V), and the structural evolution mechanism of delithiated LRLOs during heating remains unclear. Here, we combine in situ high-temperature X-ray diffraction and absorption spectroscopy to systematically investigate the structural and chemical evolution of Li1.2Ni0.2Mn0.6O2 (LLNMO) across distinct charge-discharge states. Interestingly, Ni is the first element to undergo thermally induced reduction in the charged state of LLNMO. With further increasing the temperature, Mn reduction sets in, coinciding with extensive lattice oxygen loss, and a phase transition from layered to disordered layered or Li-containing rock-salt-type phase occurs. More intriguingly, after the initial electrochemical cycle, LLNMO exhibits negative thermal expansion at low temperatures below 200 °C, which are attributed to the cycling-induced microstrain accumulation and long-range structural ordering. These findings provide a mechanistic insight into the state-of-charge-dependent thermal behavior of Li-rich layered materials and offer guidelines for designing safer, high-capacity battery materials.

The strategic valorization of semi-coking wastewater represents a critical imperative for sustainable energy transitions. Here, we report a facile solvothermal pretreatment coupled with high-temperature carbonization strategy to engineer functionalized hard carbon from phenolic resin extracted from semi-coking wastewater. The as-synthesized material delivers a remarkable specific capacity of 388 mAh g−1 and an initial Coulombic efficiency of 87% at 20 mA g−1. Critically, it also exhibits exceptional rate capability with a reversible capacity of 204 mAh g−1 at 2 A g⁻¹ and sustaining 136 mAh g−1 after 1000 cycles. Mechanistic investigations reveal that sodium storage proceeds through a synergistic adsorption-intercalation-pore filling mechanism. This work not only establishes a high-value utilization pathway for industrial wastewater but also furnishes design principles for next-generation sodium-ion battery anodes.

Direct regeneration has been regarded as the most potential recycling strategies for spent lithium-ion battery cathodes. However, excessive lithium compensation during relithiation often results in the accumulation of residual alkaline species, and the degraded crystal structure remains difficult to fully restore. Herein, a bulk-interface synergistic strategy is proposed by utilizing residual alkaline and La doping to regenerate spent Ni-rich cathodes (NCMs). The residual lithium species are converted into a Li+-conductive LiLaO2 coating layer, while La is simultaneously incorporated into the bulk lattice, enabling interfacial stabilization and structural reconstruction. This bulk-interface synergistic reconstruction can restore the degraded layered structure, and simultaneously enhance interfacial stability and Li+ transport kinetics, thereby significantly improving the electrochemical performance of regenerated cathodes. The optimized R-La10 cathode delivers an initial discharge capacity of 166.5 mAh g-1 with a capacity retention of 93.09% after 100 cycles at 0.5C. This strategy offers a brand-new perspective for the direct regeneration of spent NCM materials and has potential practical application value.

Li-rich manganese-based layered oxides (LRMO) cathode materials can deliver a high specific capacity of approximately 400 mAh g-1 under deep discharge conditions; however, they suffer from severe capacity degradation. In this work, the crystal structure evolution and strain variations of Li1.2Ni0.2Mn0.6O2 cathode materials within a wide voltage range (1.0-4.8 V) were systematically investigated using synchrotron X-ray diffraction (sXRD). As the voltage decreases below 2.0 V, the LRMO materials exhibit significant changes in microstrain, while variations in lattice parameters and unit-cell volume remain relatively small. These results indicate that the rapid capacity fading is primarily attributed to the accumulation of strain during over-lithiation.

Mullite-structured oxides exhibit excellent oxygen reduction reaction activity, possess a low thermal expansion coefficient due to their unique crystal structure, and can eliminate the need for a barrier layer and simplify the preparation process as they contain no alkaline earth elements. Thus, they hold great promise as novel cathode materials for solid oxide fuel cells. In this work, a mullite-spinel-structured SmMn2O5-NiMn2O4 (SMO-NMO) composite cathode was one-step synthesized via a solid-liquid composite route, and its in-situ self-assembly enabled good compatibility with the electrolyte without any barrier layer. Characterization results showed that the SMO:NMO = 5:5 (SN55) composite cathode overcame the bottlenecks of single-phase materials-namely, the low conductivity of pure SMO (only 0.035 S·cm–1 at 800 °C) and the insufficient oxygen reduction reaction activity of pure NMO-through a synergistic effect between the two phases. At 800 °C, the single cell delivered a peak power density of 1069.82 mW·cm–2, which was 3.24-fold and 1.20-fold higher than that of pure SMO (329.92 mW·cm–2) and NMO (890.20 mW·cm–2), respectively. Under galvanostatic operation at 750 °C (current density corresponding to 540 mA·cm–2), the SN55-based cell runs for ~150 h with only 1.6% voltage loss, corresponding to a degradation rate of 5.62%/kh, and no defects appeared at the cathode-electrolyte interface. This study provided a new route for designing barrier-layer-free cathodes for solid oxide fuel cells.

Traditional O3-type layered oxides with edge-sharing (ES) octahedra suffer from structural instability under high-voltage operation. To address this, we propose a stable edge-sharing coplanar (ESC) O2-type layered structure. In this structure, Li-O octahedra share edges on one side and faces on the other with Co-O octahedra. This ESC-configuration effectively suppresses Co migration and enhances intrinsic structural stability. Furthermore, the 180°Ni-O-TM (TM = paramagnetic transition metal) super-exchange interactions along the edge-sharing directions are introduced to improve high-voltage cycling stability. With an optimal amount of Ni, the unit-cell volume expands, reducing the activation energy for Li-ion diffusion. As a result, the modified ESC-cathode delivers a high discharge capacity of 247 mAh g-1 and a capacity retention of 79% at 1 C after 100 cycles between 3.0 and 4.65 V, far exceeding that of conventional edge-sharing LiCoO2 (210 mAh g-1, 26%). Interestingly, unlike in conventional edge-sharing layered cathodes, where Ni contributes directly to capacity, increasing Ni content in ESC cathodes leads to a decrease in capacity because additional Ni ions enter the Li layer and obstruct Li-ion diffusion pathways. Overall, this work presents an effective strategy for regulating the local coordination environment of layered oxide cathodes to achieve high performance.

High-performance solid-state lithium metal batteries capable of operating at sub-zero temperatures are desired but currently impeded by the sluggish kinetics stemming from the temperature-dependent behavior of Li+ transfer within solid electrolytes (SEs). To address this challenge, we have engineered a polyrotaxane-based fast Li-ion conductor as an innovative SE (termed PRSE-Cu), which features a metal-bridged crosslinking network within its architecture. The coordination interactions restrict the random sliding motion of the cyclic hosts, thereby forming well-ordered one-dimensional ion-conductive channels. As a result, PRSE-Cu displays enhanced Li+ conductivity. Specifically, it exhibits a high Li+ conductivity of 8.3 x 10(-4) S cm(-1) and a Li transference number of 0.75 at 25 degrees C; moreover, it boasts exceptional electrochemical stability (up to 5.0 V), and remarkable temperature adaptability (from 20 degrees C to 60 degrees C). In practical applications, a Li/PRSE-Cu/Li symmetric cell operates stably for over 4500 h at 0.1 mA cm(-2) and 25 degrees C. Notably, a Li/PRSE-Cu/LiFePO4 battery achieves stable cycling for over 1000 cycles at 0.5C and 0 degrees C, with an impressive capacity retention of 90.1 %. This study presents an innovative strategy that provides valuable insights into the design of low-temperature electrolytes and drives further advancements in solid-state Li-metal batteries.

Natrium superionic conductor (NASICON) compounds have emerged as a rising star in the field of sodium-ion batteries (SIBs) owing to their stable framework structure and high Na+ ionic conductivity. The NASICON-structured Na2VTi(PO4)3 manifests significant potential as Na+ storage material, characterized by decent rate capability and cyclability. However, the low redox potential of Ti3+/Ti4+ and undesirable energy density limit its practical applications. We developed a NASICON-structured Na3Co2/3V2/3Ti2/3(PO4)3 (NCTVP) cathode material by doping an appropriate amount of cobalt into Na2VTi(PO4)3. Cobalt doping introduces a Co3+/Co2+ redox couple at ~4.1 V and activates the V5+/V4+ redox at ~3.9 V, resulting in significantly increased medium discharge voltage and capacity. NCTVP demonstrates a high capacity of over 160 mAh g−1 at 20 mA g−1. With a medium discharge voltage of ~2.7 V, the energy density of NCTVP reaches 432.0 Wh kg−1. NCTVP also demonstrates desirable cycling stability (87.4% retention for 100 cycles at 50 mA g−1). In situ X-ray diffraction discloses a solid solution reaction mechanism for NCTVP, while the galvanostatic intermittent titration technique demonstrates fast Na+ diffusion kinetics. NCTVP also demonstrates high capacity and good cyclability in full cells. This contribution demonstrates an effective approach for the construction of NASICON materials for SIBs.

Lithium‐ion batteries are of great significance in improving people's lives by offering reliable, long‐lasting, and high‐capacity power solutions. However, safety concerns, particularly those related to electrolyte leakage under harsh conditions, pose significant obstacles to their practical applications. In this context, a biocompatible deep eutectic electrolyte (DEE) is presented formulated by blending 2,6‐dimethylpyrazine (DMPY)—a natural ingredient approved by the World Health Organization (WHO) due to its natural origin—with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in specific molar ratios. Benefitting from its abundant N atoms, DMPY molecule effectively drives Li─N coordination with Li + cations, forms hydrogen bonds with TFSI − anions, and consequently enhances the dissociation of LiTFSI—all of which trigger the formation of DEE. This DEE solution demonstrates remarkable performance characteristics, including a high Li + transference number (0.67), substantial ion conductivity (0.57 mS cm −1 at 30 °C), and moderate oxidation voltage (4.10 V vs Li/Li + ). These attributes are complemented by remarkable interface stability and long‐term cycling stability across a broad range of rates, notably at a rate of 10 C, ascribed to the generation of a robust organic–inorganic gradient solid‐electrolyte interphase. This work opens intriguing perspectives to design novel electrolytes for the demanded performance of lithium‐ion batteries while ensuring good biocompatibility.

This study presents a simple, efficient, low-cost and catalyst-free strategy for depositing fluorescent zinc oxide (ZnO) thin films on quartz substrates using radio frequency (RF) atmospheric pressure (AP) plasma enhanced chemical vapor deposition (PECVD). Diethylzinc (DEZ) and carbon dioxide (CO2) were employed as the precursor and oxidant, respectively. The plasma discharge characteristics, optical emission spectra (OES), and film growth mechanisms were systematically investigated. ZnO films exhibited high visible-light transmittance (>85%) and strong cyan fluorescence under UV irradiation, attributed to surface defects confirmed by photoluminescence (PL) spectra. X-ray photoelectron spectroscopy (XPS) revealed Zn2+ as the dominant chemical state, while amorphous structures were identified via X-ray diffraction (XRD) and Raman spectroscopy. A key innovation lies in the atmospheric pressure plasma process, which eliminates the need for high-temperature annealing or vacuum systems, significantly reducing production time and cost compared to conventional methods. Additionally, the influence of CO2 flow rate on film morphology and optical properties was elucidated, demonstrating tunable fluorescence for potential optoelectronic applications.

Solid electrolytes (SEs) are urgently needed as key components of solid-state batteries (SSBs). However, the limited physical contact between the SE and electrode gives rise to interfacial issues, causing interrupted charge transport and significant resistance at the interface. In this study, we propose a co-crystalline SE, Li(GLN)2BF4 (GLN, glutaronitrile), exhibiting a combination of properties not found in conventional ceramics, notably a low melting point of 60 degrees C and its grain-boundary fluidity. These features facilitate intimate interfacial contact without external pressure, thereby enabling liquid-like Li+ conduction for high-performance SSBs. Consequently, this SE exhibits an ionic conductivity of 1.43 x 10-4 S cm-1 at 30 degrees C and a lithium-ion transference number of 0.74. Importantly, it exhibits superior structural stability during electrochemical cycling as evidenced by in-situ wide-angle X-ray scattering. Benefitting from these properties, Li||Li symmetric cells exhibit stable operation for 600 h, while Li||LiFePO4 cells retain 92.3 % of its initial capacity after 400 cycles, all operating at room temperature and under zero externally applied pressure. This work paves new avenues for exploring co-crystalline substances that can concurrently achieve interfacial compatibility and chemical stability, in contrast to ceramic electrolytes.

Li- and Mn-rich layered oxides exhibit high specific capacity due to the cationic and anionic reaction process during high-voltage cycling (≥4.6 V). However, they face challenges such as low initial coulombic efficiency (~70 %) and poor cycling stability. Here, we propose a combination of H 3 BO 3 treatment and low temperature calcination to construct a shell with cationic vacancy on the surface of Li 1.2 Ni 0.2 Mn 0.6 O 2 (LLNMO). The H 3 BO 3 treatment produces cationic vacancy and lattice distortion, forming an oxidized O n − (0< n <2) on the surface, accompanied by electrons redistribution. Low temperature calcination eliminates lattice distortion, activates metastable O n − and promotes coherent lattice formation. In addition, the cationic vacancy shell reduces the diffusion energy barrier of Li + , allowing more Li + and oxygen to participate in deeper reactions and increasing the oxidation depth of oxygen. The modified material (LLNMO-H10-200) exhibits an initial coulombic efficiency of up to 88 % and a capacity of 256 mAh g −1 . Moreover, similar enhancements were observed with Co-containing lithium-rich materials, with a 280 mAh g −1 discharge capacity and 89 % coulombic efficiency. These findings reveal the correlation between cationic vacancy, metastable oxygen activation and bulk phase activity, offering a novel approach to enhancing the initial coulombic efficiency and cycle stability of Li-rich materials.

The utilization of high-capacity lithium-rich layered oxides (LRLOs) in lithium-ion batteries is hampered by their severe interface reactions and poor interface dynamics. Herein, an OR gate (OG) is constructed on the surface of a LRLO to alleviate its interface issues. The OR gate, consisting of layered hydrotalcite with a negatively charged interlayer and high dielectric constant, selectively enhances the Li+ transportation. Benefiting from the Li+ selectivity, the OG-coated LRLO shows outstanding cycle performance, with a capacity retention rate of 91.9% after 100 cycles at 1C (from 197.9 mA h g-1 to 182.0 mA h g-1). Moreover, the OG demonstrates a good voltage-division effect and interface stability, making it suitable for solid polymer electrolyte (SPE) systems. Interestingly, when combined with an SPE, the OG-coated LRLO delivers a capacity retention rate of 80.0% after 150 cycles at 0.2C and an ultrahigh electrode-electrolyte energy density of 437.2 W h kg-1. This approach presents a simple and effective mechanism for adapting LRLOs to solid-state batteries, enhancing the practical utilization of high-energy-density solid-state batteries.

Li5FeO4 is a promising pre-lithiation additive for the positive electrode in lithium-ion batteries, offering the potential to enhance energy density. However, its susceptibility to air degradation presents a significant challenge for commercialization. In this study, we develop an effective carbon coating strategy utilizing pitch to improve the air stability of Li5FeO4. The coating process results in the formation of a compact carbon layer on the surface of Li5FeO4 particles, enabling the coated Li5FeO4 to retain a high specific capacity of 743.4 mAh g-1 after 72 h of exposure to air with 20% relative humidity. This retention represents 92.3% of its initial capacity and 85.7% of its theoretical maximum capacity. In contrast, uncoated Li5FeO4 undergoes rapid degradation, losing most of its electrochemical activity within just 4 h under identical conditions. Beyond improving air stability, the carbon coating enhances Li5FeO4's specific capacity, rate capability, and cycling stability. To substantiate the practical application of carbon-coated Li5FeO4, we construct a pouch-type cell, which exhibits a 13.7% increase in energy density compared to the cell without the prelithiation additive. These findings collectively suggest that the carbon-coated Li5FeO4 represents a viable strategy for advancing the commercial deployment of this material in lithium-ion batteries.

Here we employ in-situ UV-Vis spectroscopy to monitor the sulfur redox reaction with oxygen-containing molecules as an additive, for example, biphenyl-4,4′-dicarboxylic acid (BDC). Furthermore, Raman spectrum, electron paramagnetic resonance (EPR), and electrospray ionization-mass spectrometry (ESI-MS) measurements reveal that the formation of BDC-S 3 •‒ complexes can establish the long-term stability of polysulfide radicals, change the kinetics of sulfur redox reaction, and then generate decent capacity retention and rate capability. According to the density functional theory (DFT) analysis, S 3 •‒ radicals are the underlying product of S 6 2‒ cleavage, owing to the decreased chemical energy and the increased stability of S 3 •‒ radicals through Lewis acid-base interaction. The assembled Li-S batteries with BDC additive deliver a high reversible capacity of 420 mA·h·g −1 over 200 cycles with over 98% Coulombic efficiency, under the current density of 0.2 C.