Weilai Yu
Life Science Research Professional 2, Chemical Engineering
All Publications
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Hyperconjugation-controlled molecular conformation weakens lithium-ion solvation and stabilizes lithium metal anodes.
Chemical science
2024
Abstract
Tuning the solvation structure of lithium ions via electrolyte engineering has proven effective for lithium metal (Li) anodes. Further advancement that bypasses the trial-and-error practice relies on the establishment of molecular design principles. Expanding the scope of our previous work on solvent fluorination, we report here an alternative design principle for non-fluorinated solvents, which potentially have reduced cost, environmental impact, and toxicity. By studying non-fluorinated ethers systematically, we found that the short-chain acetals favor the [gauche, gauche] molecular conformation due to hyperconjugation, which leads to weakened monodentate coordination with Li+. The dimethoxymethane electrolyte showed fast activation to >99% coulombic efficiency (CE) and high ionic conductivity of 8.03 mS cm-1. The electrolyte performance was demonstrated in anode-free Cu‖LFP pouch cells at current densities up to 4 mA cm-2 (70 to 100 cycles) and thin-Li‖high-loading-LFP coin cells (200-300 cycles). Overall, we demonstrated and rationalized the improvement in Li metal cyclability by the acetal structure compared to ethylene glycol ethers. We expect further improvement in performance by tuning the acetal structure.
View details for DOI 10.1039/d4sc05319b
View details for PubMedID 39568883
View details for PubMedCentralID PMC11575589
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A Transparent, Patternable, and Stretchable Conducting Polymer Solid Electrode for Dielectric Elastomer Actuators
ADVANCED FUNCTIONAL MATERIALS
2024
View details for DOI 10.1002/adfm.202411880
View details for Web of Science ID 001300258000001
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Dynamic Bubbling Balanced Proactive CO2Capture and Reduction on a Triple-Phase Interface Nanoporous Electrocatalyst.
Journal of the American Chemical Society
2024
Abstract
The formation and preservation of the active phase of the catalysts at the triple-phase interface during CO2 capture and reduction is essential for improving the conversion efficiency of CO2 electroreduction toward value-added chemicals and fuels under operational conditions. Designing such ideal catalysts that can mitigate parasitic hydrogen generation and prevent active phase degradation during the CO2 reduction reaction (CO2RR), however, remains a significant challenge. Herein, we developed an interfacial engineering strategy to build a new SnOx catalyst by invoking multiscale approaches. This catalyst features a hierarchically nanoporous structure coated with an organic F-monolayer that modifies the triple-phase interface in aqueous electrolytes, substantially reducing competing hydrogen generation (less than 5%) and enhancing CO2RR selectivity (90%). This rationally designed triple-phase interface overcomes the issue of limited CO2 solubility in aqueous electrolytes via proactive CO2 capture and reduction. Concurrently, we utilized pulsed square-wave potentials to dynamically recover the active phase for the CO2RR to regulate the production of C1 products such as formate and carbon monoxide (CO). This protocol ensures profoundly enhanced CO2RR selectivity (90%) compared with constant potential (70%) applied at -0.8 V (V vs RHE). We further achieved a mechanistic understanding of the CO2 capture and reduction processes under pulsed square-wave potentials via in situ Raman spectroscopy, thereby observing the potential-dependent intensity of Raman vibrational modes of the active phase and CO2RR intermediates. This work will inspire material design strategies by leveraging triple-phase interface engineering for emerging electrochemical processes, as technology moves toward electrification and decarbonization.
View details for DOI 10.1021/jacs.4c02786
View details for PubMedID 39049158
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Failure Process During Fast Charging of Lithium Metal Batteries with Weakly Solvating Fluoroether Electrolytes
JOURNAL OF PHYSICAL CHEMISTRY C
2024
View details for DOI 10.1021/acs.jpcc.4c01740
View details for Web of Science ID 001265561200001
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Impact of the fluorination degree of ether-based electrolyte solvents on Li-metal battery performance
JOURNAL OF MATERIALS CHEMISTRY A
2023
View details for DOI 10.1039/d3ta05535c
View details for Web of Science ID 001136975200001
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Spiral NeuroString: High-Density Soft Bioelectronic Fibers for Multimodal Sensing and Stimulation.
bioRxiv : the preprint server for biology
2023
Abstract
Bioelectronic fibers hold promise for both research and clinical applications due to their compactness, ease of implantation, and ability to incorporate various functionalities such as sensing and stimulation. However, existing devices suffer from bulkiness, rigidity, limited functionality, and low density of active components. These limitations stem from the difficulty to incorporate many components on one-dimensional (1D) fiber devices due to the incompatibility of conventional microfabrication methods (e.g., photolithography) with curved, thin and long fiber structures. Herein, we introduce a fabrication approach, ‶spiral transformation, to convert two-dimensional (2D) films containing microfabricated devices into 1D soft fibers. This approach allows for the creation of high density multimodal soft bioelectronic fibers, termed Spiral NeuroString (S-NeuroString), while enabling precise control over the longitudinal, angular, and radial positioning and distribution of the functional components. We show the utility of S-NeuroString for motility mapping, serotonin sensing, and tissue stimulation within the dynamic and soft gastrointestinal (GI) system, as well as for single-unit recordings in the brain. The described bioelectronic fibers hold great promises for next-generation multifunctional implantable electronics.
View details for DOI 10.1101/2023.10.02.560482
View details for PubMedID 37873341
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Environmentally stable and stretchable polymer electronics enabled by surface-tethered nanostructured molecular-level protection.
Nature nanotechnology
2023
Abstract
Stretchable polymer semiconductors (PSCs) are essential for soft stretchable electronics. However, their environmental stability remains a longstanding concern. Here we report a surface-tethered stretchable molecular protecting layer to realize stretchable polymer electronics that are stable in direct contact with physiological fluids, containing water, ions and biofluids. This is achieved through the covalent functionalization of fluoroalkyl chains onto a stretchable PSC film surface to form densely packed nanostructures. The nanostructured fluorinated molecular protection layer (FMPL) improves the PSC operational stability over an extended period of 82 days and maintains its protection under mechanical deformation. We attribute the ability of FMPL to block water absorption and diffusion to its hydrophobicity and high fluorination surface density. The protection effect of the FMPL (~6 nm thickness) outperforms various micrometre-thick stretchable polymer encapsulants, leading to a stable PSC charge carrier mobility of ~1 cm2 V-1 s-1 in harsh environments such as in 85-90%-humidity air for 56 days or in water or artificial sweat for 42 days (as a benchmark, the unprotected PSC mobility degraded to 10-6 cm2 V-1 s-1 in the same period). The FMPL also improved the PSC stability against photo-oxidative degradation in air. Overall, we believe that our surface tethering of the nanostructured FMPL is a promising approach to achieve highly environmentally stable and stretchable polymer electronics.
View details for DOI 10.1038/s41565-023-01418-y
View details for PubMedID 37322142
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A salt-philic, solvent-phobic interfacial coating design for lithium metal electrodes
NATURE ENERGY
2023
View details for DOI 10.1038/s41560-023-01252-5
View details for Web of Science ID 000975216800001
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Understanding the stability of semiconducting photocathodes for solar water splitting
CURRENT OPINION IN ELECTROCHEMISTRY
2023; 39
View details for DOI 10.1016/j.coelec.2023.101262
View details for Web of Science ID 000962447800001
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A general interfacial-energetics-tuning strategy for enhanced artificial photosynthesis.
Nature communications
2022; 13 (1): 7783
Abstract
The demands for cost-effective solar fuels have triggered extensive research in artificial photosynthesis, yet the efforts in designing high-performance particulate photocatalysts are largely impeded by inefficient charge separation. Because charge separation in a particulate photocatalyst is driven by asymmetric interfacial energetics between its reduction and oxidation sites, enhancing this process demands nanoscale tuning of interfacial energetics on the prerequisite of not impairing the kinetics and selectivity for surface reactions. In this study, we realize this target with a general strategy involving the application of a core/shell type cocatalyst that is demonstrated on various photocatalytic systems. The promising H2O2 generation efficiency validate our perspective on tuning interfacial energetics for enhanced charge separation and photosynthesis performance. Particularly, this strategy is highlighted on a BiVO4 system for overall H2O2 photosynthesis with a solar-to-H2O2 conversion of 0.73%.
View details for DOI 10.1038/s41467-022-35502-z
View details for PubMedID 36526643
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Degradation and Speciation of Li Salts during XPS Analysis for Battery Research
ACS ENERGY LETTERS
2022; 7 (10): 3270-3275
View details for DOI 10.1021/acsenergylett.2c01587
View details for Web of Science ID 000895677900001
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Failure Modes of Platinized pn+-GaInP Photocathodes for Solar-Driven H2 Evolution.
ACS applied materials & interfaces
2022
Abstract
The long-term stability for the hydrogen-evolution reaction (HER) of homojunction pn+-Ga0.52In0.48P photocathodes (band gap = 1.8 eV) with an electrodeposited Pt catalyst (pn+-GaInP/Pt) has been systematically evaluated in both acidic and alkaline electrolytes. Electrode dissolution during chronoamperometry was correlated with changes over time in the current density-potential (J-E) behavior to reveal the underlying failure mechanism. Pristine pn+-GaInP/Pt photocathodes yielded an open-circuit photopotential (Eoc) as positive as >1.0 V vs the potential of the reversible hydrogen electrode (RHE) and a light-limited current density (Jph) of >12 mA cm-2 (1-sun illumination). However, Eoc and Jph gradually degraded at either pH 0 or pH 14. The performance degradation was attributed to three different failure modes: (1) gradual thinning of the n+-emitter layer due to GaInP dissolution in acid; (2) active corrosion of the underlying GaAs substrate at positive potentials causing delamination of the upper GaInP epilayers; and (3) direct GaAs/electrolyte contact compromising the operational stability of the device. This work reveals the importance of both substrate stability and structural integrity of integrated photoelectrodes toward stable solar fuel generation.
View details for DOI 10.1021/acsami.2c01845
View details for PubMedID 35666827
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Tuning Fluorination of Linear Carbonate for Lithium-Ion Batteries
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2022; 169 (4)
View details for DOI 10.1149/1945-7111/ac67f5
View details for Web of Science ID 000788721400001
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Catalytic open-circuit passivation by thin metal oxide films of p-Si anodes in aqueous alkaline electrolytes
ENERGY & ENVIRONMENTAL SCIENCE
2021
View details for DOI 10.1039/d1ee03040j
View details for Web of Science ID 000728258100001
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Understanding the Stability of Etched or Platinized p-GaInP Photocathodes for Solar-Driven H2 Evolution.
ACS applied materials & interfaces
2021
Abstract
The long-term stability in acidic or alkaline aqueous electrolytes of p-Ga0.52In0.48P photocathodes, with a band gap of 1.8 eV, for the solar-driven hydrogen-evolution reaction (HER) has been evaluated from a thermodynamic, kinetic, and mechanistic perspective. At either pH 0 or pH 14, etched p-GaInP electrodes corroded cathodically under illumination and formed metallic In0 on the photoelectrode surface. In contrast, under the same conditions, electrodeposition of Pt facilitated the HER kinetics and stabilized p-GaInP/Pt photoelectrodes against such cathodic decomposition. When held at 0 V versus the reversible hydrogen electrode, p-GaInP/Pt electrodes in either pH = 0 or pH = 14 exhibited stable current densities (J) of -9 mA cm-2 for hundreds of hours under simulated 1 sun illumination. During the stability tests, the current density-potential (J-E) characteristics of the p-GaInP/Pt photoelectrodes degraded due to pH-dependent changes in the surface chemistry of the photocathode. This work provides a fundamental understanding of the stability and corrosion mechanisms of p-GaInP photocathodes that constitute a promising top light absorber for tandem solar-fuel generators.
View details for DOI 10.1021/acsami.1c18243
View details for PubMedID 34821500
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Investigations of the stability of etched or platinized p-InP(100) photocathodes for solar-driven hydrogen evolution in acidic or alkaline aqueous electrolytes
ENERGY & ENVIRONMENTAL SCIENCE
2021
View details for DOI 10.1039/d1ee02809j
View details for Web of Science ID 000707161300001
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Mixed Metal Oxide Electrodes and the Chlorine Evolution Reaction
JOURNAL OF PHYSICAL CHEMISTRY C
2021; 125 (38): 20745-20761
View details for DOI 10.1021/acs.jpcc.1c05671
View details for Web of Science ID 000704295900002
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Investigations of the stability of GaAs for photoelectrochemical H-2 evolution in acidic or alkaline aqueous electrolytes
JOURNAL OF MATERIALS CHEMISTRY A
2021; 9 (40): 22958-22972
View details for DOI 10.1039/d1ta04145b
View details for Web of Science ID 000703234700001
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Origin of the Electrical Barrier in Electrolessly Deposited Platinum Nanoparticles on p-Si Surfaces
JOURNAL OF PHYSICAL CHEMISTRY C
2021; 125 (32): 17660-17670
View details for DOI 10.1021/acs.jpcc.1c03072
View details for Web of Science ID 000687714800008
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Cathodic NH(4)(+)leaching of nitrogen impurities in CoMo thin-film electrodes in aqueous acidic solutions
SUSTAINABLE ENERGY & FUELS
2020; 4 (10): 5080-5087
View details for DOI 10.1039/d0se00674b
View details for Web of Science ID 000573449300014