Zhenan Bao

Inhibition of Calendar Aging Induced Li Metal Corrosion Using Selected Area Insulating Layer Current Collectors

Li metal is a promising anode for next-generation batteries, but its high per-cycle capacity loss hinders its commercial adoption. A major contributor is the corrosion of Li during calendar aging, which accelerates the generation of degradation byproducts, such as the solid electrolyte interphase (SEI) and isolated Li (i-Li). Here, we reveal that Li corrosion is spatially heterogeneous: five times more capacity is lost at the edge overhang area of the current collector than at the center in the coin cell form factor. To address this, we developed a selected-area insulating layer (SAIL) that prevents Li plating in the overhang, yielding a 94% reduction in corrosion-induced capacity loss. Electron microscopy and titration gas chromatography were employed to visualize the morphological heterogeneity and quantify the disconnected Li loss at the center versus the overhang. Preventing dendritic Li plating in the overhang of the current collector can therefore substantially mitigate calendar aging-induced capacity loss.

Impact of Solvent Impurities from Upscaled Synthesis and Their Purification in Lithium Metal Batteries

Fluorinated ether electrolytes are promising for high-energy-density lithium metal batteries, yet their translation to larger-scale production requires systematic control of solvent impurities generated during synthesis and purification. Using 2-(2-(2,2-difluoroethoxy)ethoxy)–1,1,1-trifluoroethane (F5DEE) as a high-performance model solvent, we compare gram- and kilogram-scale batches to correlate impurity origin, purification, and electrochemistry. Although upscaled F5DEE shows >99% purity by standard techniques, ppm-level moisture and organic impurities reduce Li Coulombic efficiency and increase cell variability. We classify impurities by generation pathway into retained intermediates, starting-material-derived analogues, side-reaction products, and purification-introduced residues. Distillation, adsorption, and reactive purification implicate water, alkoxide-derived byproducts, and amines as key performance-limiting species. However, excessive purification generates secondary impurities that degrade performance, revealing a removal–generation trade-off. Thermal, electrochemical, operando microcalorimetry, and online mass spectrometry analyses reveal impurity-dependent current-collector corrosion, heat release, gas evolution, and full-cell degradation. This route-resolved, source-to-consequence workflow provides a transferable qualification framework for electrolyte solvent scale-up.

A Skin‐Inspired High‐κ Self‐Healing Polymer for Low‐Voltage Dielectric Elastomer Actuators

Solvent-Mediated Diffusion Enables Directed Functionalization of Polymer Semiconductor Interfaces

The increasing interest in the development of intrinsically stretchable electronic devices based on polymer semiconductors (PSCs) necessitates a comprehensive understanding of the interfacial chemistry of these PSC films, alongside facile processing methods to modify these properties, which dictate layer compatibility. Solvent-mediated functionalization provides a scalable, controllable, and tunable method to target and modulate several key interfacial properties. Herein, we aim to understand the influence of solvent exposure on a blended polymer film. This is achieved through small molecule modification of a poly-thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT) and low molecular weight polybutadiene (BA)-blended elastomer film. We investigated solvent-mediated film functionalization on blended films by incorporating 1H,1H,2H,2H-perfluorodecanethiol (PFDT), as the highly fluorinated small molecule provided excellent measurement contrast throughout several characterization techniques. By comparing solvent environments that differentially swell the blended polymer films, we show programming of PFDT incorporation from uniform, through-thickness functionalization to surface-enriched gradients. Quartz crystal microbalance with dissipation monitoring (QCM-D) measurements and further corroborated with X-ray photoelectron spectroscopy (XPS) depth profiles quantified the estimated apparent mass uptake of PFDT. In a non-swelling/compacting solvent environment, QCM-D reflected a diffusion-governed uptake of PFDT with a distinct thickness-dependent concentration gradient. In contrast, swelling films with methoxyperfluorobutane (MPFB) opened diffusion pathways that facilitated PFDT penetration throughout the entire polymer network and resulted in more uniform functionalization across the entire film thickness. Collectively, these results establish a broader understanding of solvent-mediated film functionalization and further the understanding of molecular diffusion through PSC film systems.

Tuning Selectivity of Electrochemical Sensors With Polymer Coatings

Redox Staining of Metallic Lithium inside Batteries for Multimodal Visualization and Identification with Multiscale Spatial Resolution

Upcycling Commodity Polymers into Semiconductors by Sequential Grafting of Aromatic Units through Regioselective Iodination and Living Suzuki–Miyaura Catalyst-Transfer Polymerization

Stereoisomeric mixture of a multigram-synthesized helicene assembles swiftly into hierarchical ribbons via supramolecular sheets

A new helicene, with a structure inspired by perylene-diimide, is synthesized on a ten-gram scale. Although obtained as a mixture of six stereoisomers, it self-assembles rapidly into long hierarchical ribbons via single-molecule-thick sheets.

Enamine-one vitrimer organogel stretchable electrolytes for sodium-ion transport

Amino-yne-derived enamine-one vitrimers were developed as a versatile and highly tuneable avenue for deformable polymer gel electrolytes for sodium-ion transport, and the effects of varying solvent and salt were investigated.

Supramolecular Nanostructures Enabling Mechanical Reinforcement and Recognitive Self‐Healing in Elastomers

Supramolecular assembly of biological materials into fibrous structures often provides exceptional functionalities. In the case of synthetic polymers, however, it is challenging to construct fibrous structures in the condensed matrix, primarily due to limited ordering and chain mobility for supramolecular assembly. We present a design strategy of using hydrogen bonding units to facilitate supramolecular assembly in self‐healing PDMS‐based polymer films, exploring how subtle changes in alkyl spacers affect dynamic mechanical responses. We observed that increasing structural flexibility in hydrogen bonding units enables long‐range supramolecular assemblies, leading to the formation of fibrous structures. These structures endow the material with improved mechanical stability under tensile, compressive, and frictional stresses. Notably, the supramolecular assembly responds to molecular‐level changes, allowing selective self‐healing between corresponding polymers. This molecular‐level recognition gave self‐alignment in multilayer laminates, enabling autonomous healing and alignment of damaged and misaligned layers. Our findings provide new insights for designing mechanically robust, self‐healable, and multi‐functional polymers.

Revealing Solvent-Assisted Li ⁺ Transport in the Solid Electrolyte Interphase operando

The performance of energy-dense lithium metal batteries is critically influenced by the properties of the solid electrolyte interphase (SEI). Yet, progress in understanding this layer has been limited by the lack of accurate operando characterization because the SEI evolves dynamically during cycling. Here, we apply dynamic electrochemical impedance spectroscopy (dEIS) to resolve the real-time evolution of the SEI on lithium metal in ether-based electrolytes with varying degrees of fluorination. We find that faster stabilization of the compact SEI resistance correlates with improved passivation and higher Coulombic efficiency. Unexpectedly, compact SEI resistance correlates directly with Li+ solvation energy, revealing that weaker Li+ solvation increases not only bulk but also interphase resistance. These findings challenge the conventional view of the SEI as a purely solid-phase conductor and instead support a solvent-assisted Li+ transport mechanism within the compact SEI. This framework emphasizes the need to balance SEI ionic conductivity with the Li+ solvation environment to maximize lithium metal battery performance.

Sensitive Hormone and Neurotransmitter Detection with Carbon Flower Electrodes

Mechanism for the Fluctuation in Coulombic Efficiency of Lithium Metal Anodes After Calendar Aging

Calendar aging significantly affects lithium metal battery performance, with even short rest periods causing measurable drops in Coulombic efficiency (CE). However, most studies focus only on CE losses during rest, and the impact on subsequent cycles remains unclear. Here, calendar aging behavior is systematically examined in various carbonate and ether electrolytes, showing that aging influences not only CE after rest but also the following cycles. While all electrolytes show CE loss during rest, distinct CE patterns appear in the two post‐rest cycles. To clarify the mechanism behind these fluctuations, dead lithium formation during and after aging is tracked using titration gas chromatography. This also enables quantification of CE loss associated with solid electrolyte interphase (SEI) evolution. The results indicate that the interplay between SEI evolution and dead lithium recovery governs the electrolyte‐dependent CE response during post‐rest cycling. Resting frequency in full cells is further varied, and it is found that increased resting frequency does not necessarily accelerate capacity loss, suggesting that rest‐induced degradation is largely reversible. These findings provide insight into post‐calendar aging mechanisms in lithium metal batteries and highlight the dynamic nature of rest‐induced degradation.

Many-body delocalization with a two-dimensional 70-qubit superconducting quantum simulator

Elucidating the Effects of LiF on Lithium Metal Anodes

BaoPhysiology and Molecular Biology of Plants

Molecular cloning, prokaryotic expression and induction characteristics of the sesquiterpene synthase gene (AsSS15) from the Chi-Nan germplasm (Aquilaria sinensis)

Microwave engineering of tunable spin interactions with superconducting qubits

Titanium-, Nitrogen-Doped Carbon Flowers Catalyze Electrochemical Nitrate Reduction Reaction to Ammonia

An emerging design heuristic for electrochemical nitrate reduction (NO 3 RR) catalysts is synthesizing electron-deficient sites to facilitate binding of electron-rich NO 3 – . However, this rule has rarely been applied to metal-, nitrogen-doped carbon (MNC) catalysts. Titanium (Ti), with low electronegativity and high NO 3 RR reactivity, is a compelling MNC candidate. To date, atomically dispersed TiN x motifs have eluded synthesis due to the strong oxophilicity of Ti. Here, we leverage nitrogen-rich carbon flowers (CF) to overcome synthetic challenges and produce Ti-, N-doped carbon flower (TiCF) catalysts. Advanced materials characterization demonstrates that TiCF catalysts are a mixed phase material with 3/4 of Ti atoms in TiO 2 -like nanoparticles and 1/4 of Ti atoms in novel, atomically dispersed TiN x sites. TiCF achieves 61 ± 7% NH 3 -selectivity at −0.70 V vs RHE and 14 ± 5 mA/cm 2 to NH 3 formation (| j NH 3 |) at −0.85 V vs RHE in (0.1 M NaOH + 0.1 M NaNO 3 + 0.45 M Na 2 SO 4 ) electrolyte. Control studies show both CF morphology and Ti sites are essential for high NO 3 RR activity. Density functional theory calculations attribute the NO 3 RR reactivity to TiN x, which facilitates multiple bond formation with surface intermediates to promote favorable NH 3 synthesis pathways. Thus, TiCF exhibits 60× higher | j NH 3 | values than bulk Ti and NH 3 yield rates (>0.06 mmol NH 3 /h/cm 2 ) that are competitive with state-of-the-art MNC catalysts (e.g., FeNC, CuNC). TiCF introduces a new class of Ti electrocatalysts, advancing the MNC design space and sustainable NH 3 production.

Resolving Electrolyte Decomposition Products in Gas, Liquid, and Solid Phases in Lithium–Metal Batteries

Lithium (Li)-metal batteries with high-voltage cathodes are promising next-generation, high-energy automotive batteries. While ether-based electrolytes are known for their high reductive stability, their limited oxidative stability against high-voltage cathodes remains a key barrier to long-term service life. Here, we present a methodology enabling a comprehensive, quantitative assessment of cathode–electrolyte reactions, based on a model fluorinated 1,2-diethoxyethane-based electrolyte and LiNiO2 cathode. Online electrochemical mass spectroscopy at varying temperatures reveals both the thermodynamic and kinetic features of the electrolyte oxidative decomposition by quantifying gaseous byproducts and the reaction activation energy. Nuclear magnetic resonance spectroscopic results unveil alcohol and alkoxy acetic acid species as soluble decomposition products of ether electrolytes. Time-of-flight secondary ion mass spectrometry, combined with region-of-interest and spatial normalized standard deviation analyses, quantitatively determines the thickness and spatial and chemical homogeneity of the cathode–electrolyte interphase. This work establishes a quantitative methodology to assess gaseous, soluble, and solid cathode–electrolyte decomposition products.

Synchronized Breathing in Anion-Derived Interphases

Anion-derived interphases are crucial for extending the cycle life of lithium metal batteries. While their benefits are often attributed to crystalline inorganic species like LiF and Li 2 O, the role of amorphous inorganic species and the interplay between the anode-electrolyte interphase (SEI) and the cathode-electrolyte interphase (CEI) remain largely unexplored. In this study, we examine two model electrolyte systems─one with solvent-derived interphases and the other with anion-derived interphases─using advanced X-ray scattering and spectroscopy techniques. Our findings reveal that anion-derived interphases contain substantial amounts of amorphous inorganic species, leading to a unique synchronization of “breathing” between SEI and CEI. During charging, the SEI grows while the CEI shrinks; during discharging, these roles reverse. This distinctive interfacial behavior originates from the competition of deposition and dissolution of amorphous inorganics during cycling. The study highlights the unique role of amorphous inorganics in anion-derived interphases, providing new insights into improving battery performance and durability.