Wenhua Zuo

Complex degradation trajectories compromise the lifetime reliability and operational safety of lithium‐ion batteries in advanced energy‐storage systems. Aging pathways induced by temperature, rate, and voltage‐abuse stresses are often entangled in conventional health‐estimation models, limiting transferable degradation representation and future‐trajectory updating under distribution shifts. Here, a generalizable, mechanism‐anchored health‐management framework is developed for lithium‐ion batteries under heterogeneous aging conditions. Using aging‐condition identification as a proxy task, we identify a degradation‐sensitive 3.3–3.4 V charging window in LiFePO ₄ /graphite cells, where statistically selected features are linked to incremental‐capacity fingerprints. These electrochemically anchored features are integrated with a condition‐aware soft mixture‐of‐experts model to disentangle heterogeneous feature–state‐of‐health (SOH) relationships with and without condition labels during inference. Cross‐dataset continual learning enables adaptation to an unseen data source while mitigating catastrophic forgetting. Finally, data‐driven SOH observations are assimilated into a physics‐inspired parametric degradation model through an adaptive unscented Kalman filter, converting pointwise health estimates into online‐updatable degradation trajectories. The framework achieves robust SOH estimation across multi‐stress aging conditions and stable 100–300‐step look‐ahead trajectory prediction, establishing an interpretable route from electrochemical fingerprints to trajectory‐level battery prognostics.

This work reveals how VC and DTD stabilize CEI and SEI in LMFP/graphite cells, suppressing electrolyte decomposition, Mn dissolution, LiOR formation, and linking interphase evolution to explain failure and enable long-life LMFP-based batteries.

The stability of O3‐type under high‐voltage cycling is dictated by how synthesis encodes lattice strain and redox heterogeneity. Here, the role of Na:TM stoichiometry is systematically resolved by tuning the NaOH:precursor ratio during solid‐state synthesis. The stoichiometric condition (Na:TM = 1.00) yields minimized microstrain, enabling uniform O3–P3 phase evolution and homogeneous multi‐metal redox with preserved octahedral symmetry. In contrast, Na‐excess compositions inherit disordered intermediates and heterogeneous distortion fields that trigger abrupt multiphase transitions and promote localized charge redistribution. In situ XRD captures the divergence in phase‐transition pathways, TXM resolves particle‐level redox heterogeneity, and XANES corroborates a stronger and more reversible Fe redox contribution at stoichiometry, shifting to diminished Fe participation and spatially inhomogeneous redox at higher Na content. These results establish Na:TM stoichiometry as a critical synthesis parameter controlling both structural coherence and redox stability. Electrochemically, the stoichiometric composition exhibits smooth voltage profiles with minimal polarization growth and retains nearly 80% of its initial capacity after 100 cycles even at an extended 4.2 V cutoff, whereas Na‐excess compositions show significantly reduced initial coulombic efficiency and rapid voltage fade. Precise stoichiometric tuning provides a scalable route to defect‐suppressed O3 frameworks, enabling structurally resilient, high‐voltage sodium‐layered cathodes.

The transmission X-ray microscopy (TXM) based X-ray absorption near-edge structure (XANES) technique provides three-dimensional mapping of element-specific chemical states at nanometer-scale spatial resolution and micrometer-scale fields of view. However, compared to conventional volume-averaged XANES (VA-XANES) measurements, the inherently small voxel size in TXM-XANES leads to a lower signal-to-noise ratio, making full-spectrum analysis computationally demanding and less robust. Here, we present the structural and compositional conditions for a statistical white-line analysis framework under which chemical state information can be directly extracted from the white-line peak position in voxel spectra without the need for voxel-wise background subtraction or normalization, under well-defined structural and compositional conditions. The method is validated on layered oxide cathode materials, where low-order polynomial fitting accurately reproduces white-line features, and the extracted energy distributions correlate strongly with VA-XANES results. This statistical approach enables high-throughput, dose-efficient, and noise-robust chemical state quantification in TXM-XANES, offering broad applicability to functional materials requiring nanoscale oxidation-state mapping.

Gases are often by-products of battery materials during cell formation and degradation, affecting the cycle life and safety of rechargeable batteries. However, understanding gas-mediated (electro)-chemical reactions and nanoscale structural transformations during the synthesis of battery electrode materials remains challenging because of the lack of suitable characterization routes and the complexity of the interplay between thermodynamics and kinetics. Here we use operando synchrotron X-ray diffraction, in situ transmission X-ray microscopy and multiscale modelling to elucidate the reaction pathways and microstructural defect development of earth-abundant Mn-rich layered oxides as positive electrode materials for sodium-based batteries. In particular, we demonstrate the dominant role of CO₂ over O₂ and H₂O_(g) in modulating the competition between entropy and enthalpy during solid-state synthesis. Using Ni_0.25Mn_0.75CO₃ as a model precursor, we reveal that CO₂ generation favours the formation of entropy-driven metastable intermediates, suppresses closed pore/nanovoids formation and decreases chemical heterogeneity and residual lattice strain of Mn-rich layered oxides during the synthesis. This result motivates a fast-sintering strategy to promote CO₂ release, which ultimately leads to improved chemo-mechanical and electrochemical stability of the Mn-rich positive electrodes when tested in non-aqueous Na metal coin cells.

Prussian blue analogs (PBAs) represent promising cathode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity, open framework structure, and use of earth-abundant elements. However, the high-temperature structural evolution, water content effects, and thermal safety of PBAs, particularly in charged states, remain poorly understood, hindering their practical deployment. Here, we investigate Na₂Fe­[Fe­(CN)₆]·2H₂O using thermogravimetric analysis (TGA), ex situ and in situ temperature-dependent X-ray absorption spectroscopy (XAS), and accelerated rate calorimetry (ARC). TGA and ex situ XAS confirm water loss between 150 and 200 °C, resulting in Fe²⁺ oxidation, enhanced local symmetry, and uniform redox behavior that improves electrochemical performance. In situ XAS reveals irreversible structural changes above 240 °C, including ligand loss, Fe site distortion, and increased disorder, while ARC on charged electrodes shows minimal self-heating rates (<0.1 °C/min) up to 300 °C, indicating exceptional thermal stability without lattice oxygen release. These insights elucidate PBA thermal dynamics, demonstrating improved electrochemical performance of water-deficient PBAs and informing future material design and safety assessment for SIB applications.

Layered oxide battery cathodes often require extra stabilization strategies, such as surface coating or doping, to mitigate side reactions and enhance longevity. Conventional methods such as aqueous deposition and atomic layer deposition are costly and environmentally unfriendly and even damage the original structure, especially for air-sensitive sodium-ion battery (SIB) cathodes. Herein, we introduce an all-dry mechanofusion technique that modifies hydroxide precursors with TiO₂ coating before sintering with a sodium source. Using advanced characterizations including X-ray diffraction, neutron diffraction, and solid-state nuclear magnetic resonance for structural insights, X-ray absorption spectroscopy to study metal valence states, and transmission X-ray microscopy for nanoscale visualization of nickel oxidation states, we verified that postsintering transforms TiO₂ surface coating into Ti doping, leading to improved Ni-oxidation homogeneity, modified charge compensation, and enhanced thermal stability. Electrochemical tests reveal superior performance in capacity retention, rate capability, and air stability for these modified cathodes, with pouch cells maintaining over 85% capacity after 650 cycles. This method presents a sustainable, cost-effective route for advanced SIB cathode development.

Conversion electrodes offer higher reversible capacity and lower cost than conventional intercalation chemistry electrodes, but suffer from kinetic limitation and large volume expansion. Despite significant efforts, developing conversion electrodes with fast charging capability and extended lifespan remains challenging. Here, by leveraging the advantages of high-entropy doping and morphology tailoring, we develop a high-entropy hierarchical micro/nanostructured sulfoselenide Cu_0.88Sn_0.02Sb_0.02Bi_0.02Mn_0.02S_0.9Se_0.1 electrode with entropy-driven fast-charging capability. When used as a negative electrode material for sodium-ion batteries, it achieves a stable cycle life of 10,000 cycles at 30 A g⁻¹ and a high reversible capacity of 365.7 mAh g⁻¹ under fast charging in 13 seconds at 100 A g⁻¹. Moreover, high-entropy sulfoselenide also demonstrates stable cycling and good rate capability as a positive electrode material for lithium metal batteries, achieving a fast-charging capability of 37 seconds that is comparable with state-of-the-art layered cathodes. High-entropy sulfoselenide is characterized by its robust crystal structure, low ion diffusion barrier, and effective suppression of side reactions with electrolytes during cycling. Importantly, transmission X-ray microscopy affirms the chemical stability of HESSe, which underpins its fast-charging performance.