A FeCu dual single-atom catalyst with adjacent FeN4 and CuN4 sites was constructed in this work, where Cu atoms are cleverly employed as electronic and spin-regulating units to modulate the Fe active centers. Electrochemical measurements showed that the spin-modulated FeCu-based nitrogen-doped carbon (FeCu-NC) catalyst exhibited superior ORR activity, with a half-wave potential of 0.88 V and remarkable cycling stability in 0.1 M KOH compared with commercial Pt/C, as well as outstanding discharge performance in zinc-air batteries. Experimental results and theoretical calculations collectively confirmed that neighboring Cu atoms significantly enhanced the spin polarization of Fe sites. Spin-state modulation induces an upward shift of the Fe d-band center, increasing the density of reactive states near the Fermi level and strengthening Fe–O2 interactions, which facilitates O2 activation and accelerates ORR kinetics. This work demonstrates a neighboring-atom strategy for spin-state regulation in single-atom catalysts, offering new insights into spin-related oxygen activation and the design of efficient ORR catalysts.

Transition metal dissolution and redeposition (D/R) kinetics in alkaline media play a critical role in various chemical and electrochemical processes. Competitive reaction kinetics between different transition metals can modulate individual metal behavior in these processes. To date, these phenomena have remained largely unmeasured, and even when captured, they are difficult to statistically characterize due to their dynamic nature, simultaneous occurrence, and spatially heterogeneous nature. Here, we develop a statistical analysis framework based on in situ and operando X-ray fluorescence microscopy (XFM) to investigate the relative D/R kinetics of multiple transition metals in alkaline media. By employing statistical analysis, we quantify the spatial distribution of D/R species and assess the rate at which the system reaches equilibrium under varying reaction conditions. We show that pH does not simply change the rate of dissolution and redeposition, but reorganizes the cross-element kinetic correlations among Ni, Fe, and Mn and accelerates the spatial equilibration of D/R events, as quantified through correlation analysis, reaction-rate estimation, probability function distributions, and texture-based monitoring statistics. Additionally, we demonstrate how modifying the solvent environment can influence D/R kinetics, providing a pathway for tuning materials synthesis and process optimization. Our study offers valuable insights into the complex interplay between different transition metals and provides a reliable statistical framework for spatial analysis of diverse imaging data sets, enabling deeper extraction of latent information across multiple modalities.

Fast-charging lithium (Li)-ion batteries (LIBs) require electrolyte systems that simultaneously enable rapid Li-ion transport and stabilize the evolving interphases during electrochemical cycling. Here, we design and systematically evaluate four different electrolyte formulations tailored for next-generation LIBs employing a disordered rock salt (DRX) cathode and graphite (Gr) anode. Compared with the state-of-the-art carbonate-based electrolyte, the developed electrolytes deliver higher capacities and improved cycling stability at both moderate and elevated charge rates as well as better fast charge and discharge rate capabilities. Notably, Gr||DRX full cells with these electrolytes exhibit substantially higher discharge specific capacities than those using the state-of-the-art electrolyte at charge rates up to 8C (7.5 min charging time). This work also establishes clear electrolyte design principles linking solvation structures, ionic transport properties, and interphase evolutions with fast-charging performance, offering a viable pathway toward next-generation fast-charging LIBs with DRX cathodes.

Conspectus Electrochemical systems feature complex and spatially heterogeneous elemental distributions that evolve during operation. Revealing these elemental dynamics is critical to understanding operation and degradation mechanisms, and thus to improving energy storage and conversion systems. X-ray fluorescence microscopy (XFM) provides a powerful, nondestructive, and element-specific probe for mapping elemental distributions with spatial resolution across relevant length scales. These capabilities enable XFM to address key questions in electrochemical materials research, including materials synthesis and compositional engineering, post-mortem analysis of aged materials, and operando visualization of elemental redistribution during electrochemical processes. In this Account, we first introduce the mechanics and experimental setup of XFM, followed by its major capabilities and applications in electrochemical systems. We highlight its element specificity, high sensitivity, multielement detection, penetration power, and compatibility with operando and nondestructive measurements, which together make it suitable for probing complex and spatially heterogeneous electrochemical materials. We also compare XFM with other elemental analysis techniques to clarify its distinctive advantages. We then summarize ex situ XFM studies of electrochemical materials. In materials design and compositional engineering, XFM can directly verify whether intended elemental architectures are successfully realized, including surface coatings, elemental doping, and concentration-gradient designs in battery electrodes. This capability is important because the performance of engineered materials often depends not only on the presence of specific elements but also on their spatial distribution. In postcycling analysis, XFM reveals unintended elemental redistribution associated with degradation, such as transition-metal dissolution and deposition, polysulfide migration, electrolyte heterogeneity, and the formation of spatially localized reaction products or byproducts. These examples show how XFM connects elemental heterogeneity with electrochemical function and failure mechanisms. We further highlight operando and in situ XFM studies that directly visualize dynamic elemental evolution in working electrochemical systems. These studies are discussed in two categories: elemental evolution within bulk electrochemical materials and interfacial processes at electrode–electrolyte interfaces. By repeatedly probing the same region during operation, XFM can track dynamic electrochemical phenomena such as dissolution–redeposition, reversible and irreversible phase evolution, and elemental diffusion layers, which are difficult to reconstruct from post-mortem analysis alone. Dynamic behavior captured by XFM enables the correlation of spatial, temporal, and compositional information with electrochemical performance. Following representative scientific case studies, we finally discuss the current limitations and future opportunities of XFM in electrochemical research. Although XFM directly links elemental distributions with electrochemical function and degradation, its broader application is still limited by trade-offs among spatial resolution, temporal resolution, sensitivity, and field of view, especially for high-resolution, three-dimensional, and operando measurements. Future advances in higher-brilliance synchrotron sources, faster scanning schemes, improved energy-dispersive detectors, focusing optics, positioning systems, multimodal integration, real-time data processing, quantitative reconstruction, and AI/ML-assisted analysis are expected to improve throughput, spatial and temporal resolution, quantitative interpretation, and the analysis of large XFM data sets. Looking forward, XFM is expected to be applied to broader electrochemical systems and to become an increasingly powerful tool for guiding the design and mechanistic understanding of next-generation electrochemical materials and devices.

Controlling precursor chemistry is central to the scalable synthesis of sodium-ion layered oxide cathodes, yet the mechanistic link between coprecipitation routes, calcination pathways, and final electrochemical performance remains poorly understood. Here, we investigate how two distinct co-precipitation strategies influence the structure, morphology, and phase transformation of NFM precursors and their subsequent conversion into cathodes. We find that the ammonia route yields multiphasic hydroxide/oxyhydroxide precursors that undergo sluggish, multi-step phase transformation when calcined with NaOH, resulting in persistent impurity phases, structural disorder, and electrochemical irreversibility. In contrast, the citrate route produces phase-pure oxyhydroxide-like precursors that follow a clean topotactic transformation, yielding highly crystalline layered oxides with reversible electrochemical behavior. Particle morphology, which is also shaped differently by the chosen precursor synthesis route, strongly influences structural integrity during calcination. Mechanically fragile particles collapse under thermal stress, while robust particles enable coherent grain growth upon calcination. Through operando and ex-situ XRD, XAS, and electron microscopy, we reveal that precursor-derived differences in particle size, redox state, and crystallinity govern the spatial uniformity of sodiation and phase evolution. Finally, we show that carbonate-based calcination offers a robust alternative pathway by deferring sodiation to higher temperatures, allowing even mixed phase NFM-N precursors to form reversible layered cathodes. These findings highlight the critical importance of precursor–sodium source compatibility and provide design guidelines for tailoring calcination chemistry in sodium-ion battery cathode synthesis.

Fast-charging lithium-ion batteries (LIBs) require electrolyte systems that not only support rapid lithium-ion transport but also stabilize evolving interphases during electrochemical cycling. Here, we develop and evaluate four different advanced electrolytes tailored for next-generation LIBs with disordered rock salt (DRX) cathode and graphite (Gr) anode. These advanced electrolytes deliver higher capacities and improved cycling stability at moderate and elevated charge rates as well as better fast charge and discharge rate capabilities compared with the state-of-the-art carbonate-based electrolyte. Notably, Gr||DRX full cells with the new electrolytes deliver discharge specific capacities that are significantly higher than for cells with the state-of-the-art electrolyte at up to 8C charge rate (7.5 min charging). This work also establishes clear design principles linking solvation structures, ionic transport properties, and interphase evolutions to the cycling performance of DRX-based full cells, offering viable pathway toward next-generation fast-charging and high-power LIBs.

The reversibility of phase transformation influences the functionality of electrode materials in batteries. In many battery materials, nanosized grains favor phase reversibility but at the cost of cyclability due to aggravated side reactions with the electrolyte. In this study, we present a novel approach to enhance the phase transformation reversibility of layered oxide cathodes, exemplified by Na2/3Fe1/2Mn1/2O2 through proton irradiation. In addition to forming defects, proton irradiation at sufficiently high doses can subdivide single grains into multiple nanodomains without physically rupturing them. Hence, the single grains of the material assume a pseudo-secondary particle nature without reducing the overall grain size. Preserving the grain size is advantageous, as it reduces side reactions, which is not possible with conventional grain size reduction methods. While chemical transformations and defect formation induced through proton irradiation can influence the stability of battery materials, it is expected that structural reorganization due to cycling-induced phase transformation will be contained within these nanodomains. Such confinement of phase transformation is potentially responsible for enhancing the reversibility of layered oxide materials in our study. Thus, our study suggests that grain subdivision could become an effective microstructure tuning strategy for managing electrochemical cycling-induced phase changes in battery electrodes.

ABSTRACT Fluorinated solvents, salts, and binders are widely used in modern rechargeable batteries. High durability and superior high‐rate ability are often attributed to fluorine‐rich interphases or fluorine‐tuned solvation structures. To date, fluorine‐free battery development is still nascent, with the interphases and structure‐property‐performance relationship thereby remaining poorly understood. Here, we investigate the impact of anion substituents in Na‐ion salts on electrolyte ion transport properties and interphase compositions on Na‐ion anodes. A fluorine‐free sodium tetraphenylborate‐diglyme electrolyte can cycle hard carbon anode over 2000 cycles at 1C with a capacity retention exceeding 98%. Sodium metal anode exhibits stripping‐plating efficiencies of 99.93% over 1000 cycles at 0.5 mA/cm 2 and 0.5 mAh/cm 2 . The steric effect of the bulky phenyl substituent leads to negligible ion pairing and good ionic conductivity, supporting high‐rate performance of Na‐ion electrodes. We demonstrate that a transition‐metal(TM)‐free and fluorine‐free battery as proof of concept, in a perylene‐3,4,9,10‐tetracarboxylic acid diimide (PTCDI)||hard carbon full cell configuration, delivers stable cycling with a ∼85% capacity retention at 1C after 500 cycles and good fast‐charging capability reaching 80% specific energy in less than 4 min. These results show that it is possible to design TM‐free and fluorine‐free sodium ion batteries without an anion‐rich solvation structure or fluorine‐based interphases.

Morphology control is a key design parameter for sodium-ion layered oxide cathodes, yet achieving uniform precursors with balanced stoichiometry is more challenging than in lithium-ion systems due to the broader range of transition-metal chemistries involved. These complexities highlight the need for systematic comparisons of coprecipitation routes tailored to sodium-ion compositions. Here, we examine how ammonia- and citrate-based coprecipitation methods shape the morphology and composition of equimolar Ni-Fe-Mn hydroxide and oxyhydroxide precursors. We investigate how pH, ligand concentration, and temperature jointly influence precipitation onset, particle shape, and metal incorporation. In the ammonia system, precipitation proceeds readily between pH 10.5-11.5, with pH approximate to 11.0 yielding the most uniform morphology and target Ni:Fe:Mn approximate to 1:1:1 stoichiometry. Higher ammonia levels improve morphology but above similar to 1.0 M begin to delay Ni incorporation and introduce phase separation. In contrast, the citrate system shows delayed precipitation (threshold pH approximate to 11.8) but forms dense granular microspheres with narrow size distributions across 0.1-0.6 M citrate, with Fe enrichment emerging at higher ligand concentrations. X-ray diffraction reveals beta-Ni(OH)2-type hydroxides for ammonia-derived precursors and delta-FeOOH-type oxyhydroxides for citrate-derived ones. Together, these results provide practical guidance for tailoring precursor morphology and composition in Fe- and Mn-rich sodium-ion cathode materials.

Hemicelluloses have emerged as a promising alternative to traditional natural emulsifiers; however, its application is constrained by molecular heterogeneity and limited emulsifying performance. This study developed a hydrothermal-based process to extract and tailor hemicelluloses from biomass with enhanced emulsifying functionality. Switchgrass was hydrothermally treated to release hemicelluloses, which was subsequently fractionated into three molecular-weight ranges via graded ethanol precipitation. Chemical and structural analyses revealed that the hydrothermal treatment effectively disrupted the plant fiber matrix, facilitating hemicelluloses release while preserving its amphiphilic character, attributed to minor lignin grafting. Notably, high-molecular-weight hemicelluloses exhibited superior emulsifying capacity compared to low-molecular-weight hemicelluloses. The optimized hemicelluloses achieved a high emulsifying activity index of 100.4 m2/g and outstanding emulsifying stability, maintaining uniformly distributed oil droplets below 4 μm after 21 days—comparable to commercial gum arabic. This study presents a novel approach to produce high-performance hemicelluloses-based emulsifiers from biomass, supporting the advancement of sustainable food ingredients.

Polymer electrolytes are promising candidates for enabling safe, high-energy lithium batteries, particularly when paired with high-voltage layered oxide cathodes and lithium metal anodes. However, challenges at electrode|electrolyte interfaces, such as parasitic side reactions and electrolyte decomposition, have hindered the widespread adoption of polymer electrolyte-based high-voltage lithium batteries. To address these issues, this study introduces molecular ionic composites (MICs) as free-standing polymer electrolyte membranes, eliminating the need for any additional liquid electrolytes during cell assembly. MICs consist of a charged rigid-rod ionic polymer, poly-2,2″-disulfonyl-4,4'-benzidine terephthalamide (PBDT), combined with mobile ions from ionic liquids, lithium salts, and functional additives. The associative interactions between PBDT and these ions create a tunable platform with exceptional mechanical strength, moderate ionic conductivity, and enhanced electrochemical stability of polymer electrolyte over a wide temperature range. The optimized MIC electrolytes exhibit high ionic conductivity (3.21 mS cm-1 at 60 °C), a wide electrochemical stability window (5 V vs Li|Li+ based on linear sweep voltammetry), and excellent mechanical properties (tensile strength of 6.3 MPa, elastic modulus of 450 MPa). Furthermore, MICs enable good cycling stability in NMC811||Li metal cells, delivering an initial specific discharge capacity of 212 mAh g-1 and 93% capacity retention after 100 cycles at 2.8-4.4 V, C/3, and 60 °C. These results underscore the potential of MICs as a promising electrolyte platform for next-generation high-voltage lithium batteries and broader electrochemical energy storage applications.

With the increase in massive applications of electric vehicles, there is an increasing demand for battery systems with fast charging capability, low cost and wide temperature range. It is well known that the electrolyte in a battery plays a critical role in battery performance because it determines the rate of ion transport and the properties of its derived electrode/electrolyte interphases on both cathode and anode of the battery. In this study, we report the development of nonaqueous electrolytes for lithium-ion batteries using cost-effective cathode and anode materials to achieve fast-charging capability and wide-temperature application. The electrolyte solvation structure, the electrode/electrolyte interphases and the battery performance are characterized and studied to establish their correlations and fundamental mechanisms. More detailed information will be discussed during the presentation.

Lithium (Li)‐ and manganese (Mn)‐rich disordered rock salt (DRX) materials are promising cathode materials for next‐generation Li‐ion batteries. Although these cathode materials are Li‐ions rich in their pristine state, their incorporation into full cells results in challenges with maintaining Li‐ion inventory during cycling. Herein, the degradation mechanisms of DRX materials in different DRX||Graphite full cells are reported. It is found that DRX electrodes contain Li impurities, primarily due to the environmental sensitivity of mechanochemically synthesized DRX materials during sample transfer and storage. In addition, the structural instability of DRX triggers Mn dissolution. Dissolved Mn ions react with exposed Li x C y compounds and induce electrolyte decomposition on the anode, further depleting Li‐ion inventory. Control experiments involving the pre‐addition of Mn 2 ⁺ provide clear evidence of the impact of Mn dissolution on Li‐ion inventory. The electrochemical activation process can stabilize DRX, alleviate Mn dissolution and thus mitigate the loss of Li‐ion inventory. These mechanistic insights inform the development of chemical pre‐lithiation and electrolyte additive strategies to collectively passivate interfaces, mitigate the effects of trace dissolved Mn ions, and preserve Li‐ion inventory. Ultimately, the DRX||Graphite full cell achieves highly reversible electrochemical reactions with a high capacity retention. This study fills a research gap in DRX‐based full cells and provides insights into degradation mechanisms and optimization strategies for their practical use.

Regulating electron transfer through defect engineering to selectively catalyze the cleavage of lignin C-O bonds is of significant scientific importance for the directed conversion of biomass into high-value chemicals. However, the precise dissociation of chemical bonds remains challenging. In this study, a 2D nanoflower-like NiAl-MMO catalyst was successfully constructed via a hydrothermal in situ pyrolysis synergistic strategy. An Al doping strategy was employed to fabricate Ni and Al3+-Ov (Ov denotes oxygen vacancy) synergistic dual active centers in NiAl-MMO. The research results indicate that the introduction of Al significantly enhances the catalytic performance. When an appropriate amount of Al is doped, it not only effectively increases the specific surface area of the catalyst and optimizes its pore structure but also enables the formation of moderate-strength interactions between metallic Ni and Al. Meanwhile, the presence of Al induces an increase in the concentration of Ov in the catalyst. Ov can regulate the electronic state of Ni active sites by modulating electron density while also enhancing the Lewis acidity of the catalyst, thereby improving its adsorption capacity for reactants. This electronic regulation optimized the electronic coupling environment of bimetallic sites and significantly strengthened the synergistic effect between Al3+-Ov and Ni sites, improving the hydrogen activation capability and directed C-O bond cleavage performance of the catalytic system. The catalyst exhibited excellent C-O bond dissociation selectivity in the lignin hydrodeoxygenation (HDO) process with a total liquid yield of 45.7 wt % (68.4% selectivity for C6+ cyclohexanol), providing a new approach for the synthesis of aviation fuel precursors. This work offers a novel strategy for the directed conversion of lignin through the synergistic regulation of interfacial defects and electronic structures.

High-efficiency antimony sulfide (Sb2S3) solar cells have successfully learned from the device structure of perovskite solar cells and often use spiro-OMeTAD as the hole-transporting layer (HTL). However, the stability of spiro-OMeTAD under an atmospheric environment is poor. It is generally believed that copper-based semiconductor nanocrystals (NCs), demonstrating appropriate valence band maximum (VBM), remarkable stability, and abundant elements, are suitable for the HTLs. In practice, however, related research has mainly focused on perovskite solar cells. In this work, Cu2SnS3, Cu2ZnSnS4, and CuInS2 nanocrystals are synthesized by the hot injection method and successfully used as HTLs in high-efficiency Sb2S3 solar cells. Through hexanethiol ligand exchange, dense and continuous copper-based semiconductor nanocrystal films are prepared by the spin coating method. Furthermore, the device performances of Sb2S3 solar cells based on Cu2SnS3, Cu2ZnSnS4, and CuInS2 HTLs are up to 6.52, 6.70, and 7.06%, respectively. It shows a comparable performance with the traditional spiro-OMeTAD (7.10%) and significantly improved stability compared to the Sb2S3 solar cell based on the spiro-OMeTAD HTL in an air atmosphere. This work highlights the importance of HTL in achieving high-efficiency and stable Sb2S3 optoelectronic devices.

Designing interphases in Na-ion batteries (NIBs) faces challenges due to the microstructural heterogeneity of hard carbon electrodes, which features competing Na-ion storage mechanisms. These mechanisms have varying requirements for electrolytes and interphases, affecting rate performance and cycle life. This presentation will detail our advancements in controlling interphase dynamics through tailored electrolytes and hard carbon structures. We will first overview our development of hard carbon materials, including powders and free-standing membranes. Next, we will explore new insights into the solid-electrolyte interphase (SEI) on hard carbon surfaces, where the dynamic SEI evolution can be manipulated to allow the system to reversibly switch between ion intercalation (batteries) and ion adsorption (capacitors). This switch, influenced by SEI dynamics under different thermal conditions, allows for distinct battery and capacitive processes within a narrow temperature range. We will then introduce an electrochemical method to heal the SEI layer in situ. These findings will inform the design of improved SEIs for future battery technologies.

The oxygen evolution reaction is a key process in many energy technologies, but improving its efficiency remains challenging due to the energy scaling relationships that limit the reaction kinetics on conventional single-active-site solid catalysts. Here we report a cooperative solid–molecular mechanism for oxygen evolution on NiFe-based hydroxide electrocatalysts. By identifying the critical interfacial species and understanding their dynamics, we find that molecular FeO42− species, derived from the dissolution of Fe from the solid catalyst, act as molecular co-catalysts that participate in the critical O–O bond-formation step along with solid sites. This synergistic mechanism, involving both solid and molecular active species, circumvents the typical scaling limitations observed for solid catalysts alone. Our findings reveal an unconventional solid–molecular mechanism that governs electrocatalysis at the solid–liquid interface and suggest a strategy for transcending scaling constraints through cooperative multi-site catalysis. NiFe-based catalysts are promising for water oxidation in alkaline electrolytes, but their dynamic structure under operation hinders the establishment of design principles for improved catalytic performance. Now a water oxidation mechanism on mixed NiFe hydroxide catalysts is proposed that involves dissolved FeO42− species acting as co-catalysts.

Ion intercalation is a versatile process that involves ion extraction and reinsertion, accompanied by redox processes and structural changes in the bulk of a material. Transition metal oxides with a layered structure have received significant attention as secondary battery electrodes thanks to their ability to accommodate a wide range of mobile cations with varying radii and charges (e.g., H + , Li + , Na + , K + , Zn 2+ , Ca 2+ ). Numerous transition metal oxides (A x TMO 2 , A is the mobile cation, and TM is the transition metal) with varying layer stacking sequences have been developed by modulating both the A and TM chemistry, making this materials class highly versatile with tunable intercalation properties. The ability to accommodate various mobile ions within a layered structure also opens opportunities for synthesizing novel metastable materials, and, for examining the links between electro-chemo-mechanics and phase behavior. Cation exchange through (electro)chemical methods is an effective approach to synthesize metastable compounds with new crystal structures, chemical compositions, and a tunable intercalation chemistry. By utilizing Li + / Na + or Na + / K + exchange reactions, researchers have successfully obtained unique structures that are otherwise impossible to synthesize through traditional methods, thereby allowing for the modulation of their properties as battery electrode materials. However, it is unclear how ion exchange evolves as a function of cycling and, at the material level, how it impacts the (de)intercalation properties over time. The spatial distribution of exchanged ions within the electrode structure remains unclear, particularly as a function of state of charge. Therefore, in the presentation, we will discuss the evolution of the long-range and local structure, and the ion (de)intercalation properties of the Ni-rich cathode during electrochemical Li / Na ion exchange using a variety of operando and ex situ characterizations, including diffraction, spectroscopy, and imaging techniques.

Biomass-derived functional carbon materials have attracted increasing research attention due to their cost-effectiveness, environmental friendliness, and easy adjustability of compositions and structures. Especially, for sodium-ion batteries (SIBs), which are widely recognized as a promising alternative to lithium-ion batteries, biomass-derived hard carbon holds the greatest potential as an anode material for commercialization in the near future. In this paper, through a facile carbonization process, a multi-dimensional structured N-doped hard carbon with rational pores and defects has been successfully synthesized from an abundant and easy-accessible biomass precursor of ceiba flower, which delivers a remarkable initial coulombic efficiency of 83.2%. When incorporated with ZnIn2S4 nanoarchitectures, the fabricated composites maintain the multi-dimensional structures with further-optimized pores, defects and electronic structures, achieving a high reversible capacity of 510.2 mA h g-1 after 1000 cycles at 1 A g-1. Considering the low-cost raw materials, environment-friendly and facile synthetic process, high initial coulombic efficiency and high reversible capacity, these ceiba-derived materials hold great application potential as anode materials for high-performance SIBs.

The broader application of nickel-rich layered oxides as positive electrode materials for lithium-ion batteries has been hindered by their high manufacturing cost and inferior cycling stability. Thermal processing, which is integral to electrode materials manufacturing and fundamental in materials science, has not been fully utilized to design advanced positive electrode materials. Herein, we demonstrate the capability of using quenching heat treatment to regulate Li distribution and modulate electronic structure near particle surface. The resulting materials exhibit less parasitic reactions with the electrolyte and an improved charge distribution homogeneity in secondary particles, leading to more stable cycling performance at high voltages (4.5 V vs Li/Li+). Our synchrotron X-ray analyses reveal the underlying interplay between surface structure and bulk charge distribution in positive electrode materials particles. While strategies used to stabilize positive electrode materials through compositional control, surface modification, and electrolyte engineering have become mature, thermal processing can be advantageous to further improve positive electrode materials manufacturing. Nickel-rich Li-ion positive electrodes face challenges such as high cost and poor cycling stability. Here, authors show that quenching heat treatment can lead to more stable performance at high voltages, with synchrotron analyses revealing the roles of surface chemistry and bulk charge distribution.