Gel polymer electrolytes offer the advantage of simultaneously maintaining high ionic conductivity and improved safety, yet they remain ineffective in suppressing thermal runaway under elevated temperatures. Herein, we report a thermoresponsive gel polymer electrolyte (TGPE) enabled by retained double bonds that provides an intrinsic thermal shutdown through retained double bonds. The TGPE is constructed by polymerizing triallyl isocyanurate (TAIC) with pentaerythritol tetraacrylate (PETEA) at 60 degrees C, forming a partially cross-linked network with abundant unreacted C=C bonds. Upon overheating above 115 degrees C, these residual bonds undergo rapid secondary cross-linking within 15 min, converting the electrolyte from an ion-conductive gel into a dense ion-blocking gel. This transition sharply increases internal resistance, suppresses ionic transport, and results in nearly zero capacity with a current reduction exceeding 90%. Under normal operation, the TGPE exhibits high ionic conductivity (0.54 mS cm-1 at 30 degrees C), a wide electrochemical stability window up to 4.35 V versus Li+/Li, and stable cycling performance with 89.3% capacity retention after 500 cycles in Li||LiFePO4 cells. More importantly, the autonomous thermal shutdown significantly delays thermal runaway, increasing the triggering temperature (T 2) from 108.7 to 146.3 degrees C in 3.0 Ah Graphite||LiFePO4 pouch cells and from 114.9 to 135.9 degrees C in 1.0 Ah SiC||NCM811 cells. This bond-retention-activated densification strategy offers a scalable route toward intrinsically safe lithium-ion batteries by balancing electrochemical performance and thermal safety.

Achieving extreme fast charging (XFC, similar to 6 C) capability remains a challenge for Li ion batteries in electric vehicle applications. This work employs time-resolved X-ray diffraction (XRD) to investigate the structural evolution and capacity contributions of a series of LiNixCoyMnzO2 (x + y + z = 1, NCM) cathodes under XFC conditions. All NCM cathodes (NCM-92, NCM-83, and NCM-622) deliver similar to 60 % of their capacities with less than 2 % unit cell volume expansion during the H1-H2 phase transition, but the subsequent H2-H3 phase transition exhibits significant compositional and rate dependence. The NCM-92 cathode shows a maximum d-spacing shrinkage of -5.3 % at 6 C, which is larger than that of NCM-83 (-4.1 %) and NCM-622 (-0.05 %). Furthermore, NCM-92 follows a "phase heterogeneity" pathway for its structural evolution above 4.2 V, distinct from the "solid-solution" pathway observed in NCM-83 and NCM-622. This phase heterogeneity is evidenced by the splitting of the (0 0 3) diffraction peak and a decrease in intensity during the H2-H3 phase transition, indicating the formation of lithium-rich/depleted domains. These findings establish a direct correlation between cathode composition, structural dynamics, and XFC performance, highlighting a critical trade-off between structural stability and fast-charging capability in nickel-rich layered oxides. (c) 2025 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Layered metal oxide cathodes suffer from pronounced structural degradation under high charging cut-off voltages, limiting their high-energy applications. While electrochemical degradation mechanisms have been extensively studied, the role of mechanical deformation introduced during electrode calendering remains largely unexplored. Here, using LiCoO2 (LCO) as a model system, we demonstrate that industry-scale roll press calendering induces shear strain at the atomic scale, which triggers the O3-to-O1 phase transition during high-voltage ageing at 4.48 V. The propagation of shear strain during cycling leads to inhomogeneous layer gliding and structural deformation, contributing to the heterogeneous lithium distribution at the atomic scale. We establish a mechanistic link between calendering-induced shear strain and high-voltage structural failure. To mitigate this challenge, we have developed an isostatic calendering method that suppresses shear strain in LiCoO2 while achieving an industry-level high tapped density (4.2 g/cm3), resulting in enhanced structural integrity and electrochemical stability. The findings position mechanically induced strain as a critical degradation driver in layered oxide cathodes, underscoring the importance of coupling material design and electrode engineering to advance battery technologies.

The phase changes of sodium layered oxide (SLO) cathodes occurring at high voltage could raise structural instability and oxidative activity with electrolyte. Understanding the evolving processes and key influence factors of these phase changes is critical to find targeted strategies for improvements. Herein, we demonstrate that metal migration, a frequently overlooked influence factor, can induce gliding of transition metal layers and thus a P to O phase transition. Also, the thermodynamic voltage, Na+ distribution, and lattice change induced by the P to O phase transition can be finely tuned by adjusting the metal migration properties. As a proof-of-concept, an O3type SLO cathode with an O3 solid-solution phase transition induced by Zn migration is designed, which exhibits a high reversible capacity of 139 mAh/g at 4.1 V in pouch-type sodium-ion full cells along with excellent cycling stability, enhanced rate capability, and greatly suppressed gas evolution.

Transition metal (TM) dissolution and crosstalk are one of the main degradation mechanisms for the capacity fading of lithium-ion batteries (LIBs). Although significant efforts have been devoted to elucidating the origins of TM dissolution, its crosstalk effect on the anode interface is unclear, especially for its specific chemical state and electrochemical behavior. Herein, the interplay between the dissolved Mn 2+ and the solid electrolyte interphases (SEI) on graphite anode is revealed by different characterization techniques, such as Raman spectroscopy, cryogenic transmission electron microscopy, electron energy loss spectroscopy, and time-of-flight secondary ion mass spectrometry. The results demonstrate that Mn 2+ is inclined to coordinate with ethylene carbonate (EC), which is easily decomposed and generates organic-Mn 2+ species and gaseous byproducts. These gases disrupt the SEI structure, facilitate electrolyte infiltration, and induce continuous growth of the SEI layer. This study deepens the understanding of TM crosstalk on SEI properties and LIB performance, offering potential strategies for enhancing battery durability and performance.

Transition metal (TM) dissolution and crosstalk are one of the main degradation mechanisms for the capacity fading of lithium‐ion batteries (LIBs). Although significant efforts have been devoted to elucidating the origins of TM dissolution, its crosstalk effect on the anode interface is unclear, especially for its specific chemical state and electrochemical behavior. Herein, the interplay between the dissolved Mn 2+ and the solid electrolyte interphases (SEI) on graphite anode is revealed by different characterization techniques, such as Raman spectroscopy, cryogenic transmission electron microscopy, electron energy loss spectroscopy, and time‐of‐flight secondary ion mass spectrometry. The results demonstrate that Mn 2+ is inclined to coordinate with ethylene carbonate (EC), which is easily decomposed and generates organic‐Mn 2+ species and gaseous byproducts. These gases disrupt the SEI structure, facilitate electrolyte infiltration, and induce continuous growth of the SEI layer. This study deepens the understanding of TM crosstalk on SEI properties and LIB performance, offering potential strategies for enhancing battery durability and performance.

KLaTiO4 is a promising photocatalyst, producing 9.54(11) µmol of hydrogen gas per hour. Its high bandgap, of 4.09eV, makes it unsuitable for direct photocatalysis under sunlight irradiation. In this study two novel methods of doping KLaTiO4 with nitrogen were studied, in an attempt to reduce the bandgap of KLaTiO4 without inducing structural degradation of the photocatalyst, which adversely affects the hydrogen evolution rate. The first method involves post-synthesis calcination of KLaTiO4 with urea under a nitrogen atmosphere, and the second method attempts to introduce nitrogen during synthesis, by replacing TiO2 with TiN as a starting reagent. The samples were structurally characterised using powder X-ray diffraction and their bandgap and photocatalytic performance determined by Tauc plot and hydrogen evolution testing. Density Function Theory calculations have been used to probe the likely site of nitrogen doping.

The high energy/power lithium-ion battery using LiNi0.5Co0.2Mn0.3O2 (NCM523 HEP LIB) has an excellent trade-off between specific capacity, cost, and stable thermal characteristics. However, it still brings a massive challenge for power improvement under low temperatures. Deeply understanding the electrode interface reaction mechanism is crucial to solving this problem. This work studies the impedance spectrum characteristics of commercial symmetric batteries under different states of charge (SOCs) and temperatures. The changing tendencies of the Li+ diffusion resistance Rion and charge transfer resistance Rct with temperature and SOC are explored. Moreover, one quantitative parameter, § ≡ Rct/Rion, is introduced to identify the boundary conditions of the rate control step inside the porous electrode. This work points out the direction to design and improve performance for commercial HEP LIB with common temperature and charging range of users.

Boosting the ultralow temperature (below −30 °C) performance of Na‐ion hybrid capacitors (SIHCs), which integrate the high energy density of batteries with the high output power and long life of supercapacitors, is critical for the application of advanced electronics in extreme environments. However, their low‐temperature performance, especially fast charging capability, is hindered by difficult desolvation and slow pass solid electrolyte interphase (SEI) together with sluggish diffusion within the electrode. Herein, a “single‐solute–single‐solvent” electrolyte is developed and a through‐hole hollow carbon sphere (TH‐HCS) is constructed, and it is demonstrated through theoretical calculations and experimental investigations that the weakly solvated structure and high ionic conductivity facilitate the Na + transportation at low temperatures, the highly fluorinated SEI facilitates the Na + migration, and the through‐hole hollow structure alleviates the volume expansion during sodiation, thus ensuring fast kinetics and structural stability. As expected, TH‐HCS using this electrolyte exhibits a high specific capacity of 87.5 mAh g −1 after 11 000 cycles at 1.0 A g −1 and −40 °C. Coupled with activated carbon, the assembled SIHC displays an energy density of 106.1 and 52.0 Wh kg −1 at 25 and −40 °C, respectively, far exceeding the performance of commercial energy storage systems at low temperature.

Therational design of solid electrolytes for the next-generationbatteries entails an accurate understanding of ionic transport mechanisms.To elucidate the detailed ion hopping processes in different coordinateenvironments, two solid electrolytes, LiTi2(PO4)(3) and Li3Ti2(PO4)(3), with the same NASICON-type framework but different sitesfor accommodating mobile ions, were synthesized and investigated by in situ neutron diffraction and theoretical calculations.The temperature-dependent anisotropic thermal vibrational ellipsoidsand migration paths from the maximum entropy method (MEM) indicatedthat Li ions move faster at higher coordinate architectures, exhibitingthree-dimensional (3D) diffusion pathways. In this rhombohedral structure,"one" node (M1 site) out of "three" interconnectedtransition sites was found to be the lithium configuration of NASICON.Li ions located at the nodes along the 3D pathway in LiTi2(PO4)(3) can only drive out another Li-ion speciesat the node site, while Li ions located at transition sites betweentwo nodes in Li3Ti2(PO4)(3) have repulsive force from their five surrounding Li ions. Thesedifferent configurations lead to distinct overall transport modes.In LiTi2(PO4)(3), concerted Li ionstransport along a separated chain, while in Li3Ti2(PO4)(3), concerted motion occurs along multiplecooperating chains in the 3D channels. Theoretical calculations furtherindicated that a larger diffusion bottleneck size of Li3Ti2(PO4)(3) enables lower hoppingenergy compared to LiTi2(PO4)(3). Thisstudy clarifies the detailed ionic hopping processes and the underlyingstructure-conductivity relationships. Overall, these resultselucidate the synergistic events in Li-ion hopping from thermodynamicand kinetic points of view, which will greatly benefit the rationaldesign of solid electrolytes for next-generation batteries.

Molecular O2 has been clarified as an important O-oxidation model in anionic redox, the charge compensation provided by which pushes energy-density limits of layered oxide cathodes. However, how to confine the bulkformed molecular O2 and retard its conversation to free gaseous O2 (& UARR;), an origin of unstable redox electrochemistry, remains open questions. Here, we propose a strategy via tuning relative values of Mott-Hubbard U and charge-transfer energy & UDelta; to suppress charge transfer on surface anions to confine the bulk molecular O2. Supported by theoretical calculations, Nb5+ without 4d electrons which can enable U < < & UDelta; is selected as a charge-transfer insulator. The thus Nb5+-surface-tailored model compound Na0.67Fe0.5Mn0.5O2 shows an oxygenredox-inactive surface and well-confined bulk molecular O2 as directly uncovered by soft X-ray absorption spectroscopy and 50 K-electron paramagnetic resonance results respectively. Meanwhile, a stable redox electrochemistry with enhanced cycling stability, inhibited voltage decay and eliminated P2-O2 phase transitions is observed because of the well-caged bulk O2. More broadly, this work presents a versatile access to stabilize the important O-oxidation model, enriching approaches of stabilizing the anionic redox electrochemistry.

The thermoelectric properties of nine Zintl-phase semiconductors II-I-V (II = Ca, Sr, Ba, I = Cu, Ag, Au, and V = As, Sb, Bi) are studied by using first-principles calculations. The electronic and thermal transport properties are calculated to elucidate the thermoelectric performance. The electron localization functions and crystal orbital Hamilton population show regular and anisotropic bonding in II-I-V, which makes anisotropic thermal and electronic transport properties. The phonon dispersion curve also shows element dependent distributions. We suggest that the regularity of phonon and electron distribution makes the adjusting of thermoelectric performance in P63/mmc type Zintl-phase compounds possible. The mix of ionic and weak covalent bonding leads to the coexistence of soft phonon modes and favorable electronic properties and thus a high figure of merit (0.41-0.94). We also investigate the three phonon scattering properties. The importance of acoustic phonon softening in lowering thermal conductivity is observed. The symmetry-based three-phonon scattering pathways demonstrate the possible intense phonon-phonon scattering. These data provide a deep understanding of the thermoelectric properties in Zintl-phase compounds.

Full-Heusler thermoelectric materials have intrinsically low lattice thermal conductivity. Our first-principles calculations show that Ba2AgSb is a semiconductor with an indirect band gap of 0.49 eV. The electronic band degeneracy and pockets near the Fermi level facilitate electron transport. The short phonon relaxation time, small group velocity (1.89 km s(-1)), and large phonon scattering space reflect the intense phonon-phonon scattering. The large Gruneisen parameter (1.44) accounts for the strong phonon anharmonicity, thus the low lattice thermal conductivity of 0.5 W m(-1) K-1 at 800 K. The isotropic figure of merit with a maximum value of 4.7 at 750 K is comparable to that of reported materials. The distribution of phonon momentum uncovers the important role of Ag in resisting thermal transport. The analysis of symmetry-based phonon-phonon scattering routes reveals the significance of symmetry on phonon scattering. The crystal structure of Ba2AgSb can be used to regulate chemical elements to build high-performance thermoelectric materials. Our calculations provide an effective way to design thermoelectric materials, stimulating the study of full-Heusler materials.

Na-based layered transition metal oxides with O3-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the O-type Na-coordinate environment compromises their rate and cycle capability, hindering their practical application. Here, we report an interphase-structure tailoring strategy that improves the electrochemical properties of O3-type layered cathodes achieved through surface coating and doping processes. Specifically, a Zr-doped interphase structure is designed in the model compound NaNi1/3Mn1/3Fe1/3O2 using the ionic conductor Na3Zr2Si2PO12 as the surface coating material and Zr-dopant provider. We discover that the modified NaNi1/3Mn1/3Fe1/3O2 cathode shows a stable Na-storage structure as well as an enhanced rate/cycle capability. Combined with theoretical calculations, it is suggested that the superior electrochemical performances originate from the Zr-doped interphase structure, which has an enlarged Na layer spacing that forms favorable Na-ion diffusion channels. This work highlights a general material interface optimization method which opens a new perspective for fabricating high-performance electrodes for Na-ion batteries and beyond.

Transition-metal chalcogenides (TMCs) show great potential as highly efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER). Yet the electrochemical conversion into oxides/ hydroxides remains poorly understood. In this work, we develop a built-in, electric-field-induced surface reconstruction strategy for ultra-fast self-activation of transition metal sites in self-supporting CoS2/CuS heterostructures. The activated CoS2/CuS grown on carbon cloth with oxygenated surface species displays an outstanding OER electrocatalytic activity with ultra-low overpotentials of only 136 mV at the current density of 10 mA cm(-2) and 266 mV at 100mA cm(-2) in 1.0MKOH. Comparative studies via synchrotron radiation X-ray absorption spectroscopy and theoretical calculations are employed to elucidate that the built-in electric field within heterointerfaces significantly promotes the reconstruction efficiency by decreasing the formation energy of (oxy) hydroxide species. We believe this work provides new perspectives to conceive catalysts with ultra-low overpotentials and complements the fundamental comprehension of TMCs' self-reconstruction mechanism.

The interface compatibility lies in the heart of present investigations on solid-state batteries, now facing significant challenges in practical use. The non-coherent interface structure with the underlying complex electrochemical processes evolves dynamically to pregnant the unfriend seeds to degrade the battery performance. Therefore, interface engineering (or control) in solid-state batteries gives birth to a new theme as 'the interface is equal to the battery'. In this context, a facile but robust technique is proposed here by smoothing the Li1.5Al0.5Ge1.5P3O12 (LAGP) ceramic pellet with a mirror-like surface, which is found operational in running a solid battery in unprecedentedly a thousand cycles with capacity retention of 80% at 0.5C, 50 degrees C. Such an unconventional operation is, as a matter of fact, largely decreasing the physically interface contact but proved powerful in guiding the Li-ion homogeneous deposition. Moreover, the self-generated LiF involved interphase layer works efficiently to dynamically balance structural and electrochemical stabilities, where the LiF is introduced by the in-situ polymerization of tiny liquid electrolytes. Hence, the profound results draw the incompatible interface issues forth to the component adjustment of interphases, namely in search for rational descriptions to connect the solid-state electrolyte and electrodes, which probably holds the key to unlocking the high energy density solid-state batteries.

Based on the theoretic analysis of Ti2B monolayer by first-principles calculations, we find that the Ti2B mono layer is one of the promising candidates for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) electrode materials. In comparison with other materials, Ti2B monolayer exhibits relatively high capacity (503.1 mA h g(-1)) and low diffusion barriers (17.2-23.5 meV). During the ion insertion/retraction, extremely high structure stability is indicated by the nearly invisible volumetric variation, and steady metallic character is manifested by the abundant electrons near the Fermi level. In the ground state of ferromagnetism, the magnetic effects are revealed on the thermal stability, charge transfer, ions diffusion, operating voltage and storage capacity.

Thermoelectric materials are critical parts in thermal electric devices. Here, Zintl phase BaAgSb in space group of P6 3 /mmc is reported as a promising thermoelectric material in density function theory. The anisotropic lattice thermal conductivity and phonon transport properties are investigated in theory. The strong phonon-phonon scattering in BaAgSb exhibits ultra-low lattice thermal conductivity of 0.59 W⋅m −1 ⋅K −1 along c -axis at 800 K, and high thermoelectric performance ZT = 0.94 at 400 K. The mix of covalent and ionic bond supports high carrier mobility and low thermal conductivity. The unusual features make BaAgSb a potential thermoelectric material.