Cheng-Wei Lin

Lead-free Rb ₂ SnBr ₆ prepared by a modified hot-injection method via transient ligand-mediated lamellar superstructures yields phase-pure stable cubic nanocrystals for photocatalytic dye degradation.

Advanced electrolyte configurations are essential for next-generation lithium batteries. Glyme ether electrolytes are attractive due to their low reactivity with lithium metal. However, the commonly used lithium bis(fluorosulfonyl)imide (LiFSI) salt exhibits poor anodic stability due to severe aluminum corrosion. In contrast, lithium hexafluorophosphate (LiPF6) offers excellent aluminum compatibility at high voltages but exhibits abnormally low solubility in glyme ether solvents, limiting its application in lithium batteries. The underlying mechanism for this behavior remains unclear. Herein, we show that the low solubility of LiPF6 in glyme ether solvents originates from a “dissociation-solvation-reprecipitation” mechanism. Taking LiPF6 in dimethoxyethane (DME) as an example, weak dielectric screening and high molecular symmetry of glyme ethers promote the association of DME-solvated Li+ and PF6–, leading to the formation of an insoluble solvate crystal, Li(DME)2PF6. Based on this mechanism, we further predict and experimentally verify a solubility-inverted region (SIR), in which LiPF6 and glyme ethers can reform a homogeneous solution once the LiPF6 concentration exceeds a critical threshold, provided that the eutectic point between the Li(ether)xPF6 solvate crystal and LiPF6 falls below the operating temperature. Consequently, an electrolyte consisting of 5.0 M LiPF6 in DME/DEE (1:1 vol %) exhibits anodic stability up to 7.0 V vs Li+/Li. A Li||LiNi0.8Co0.1Mn0.1O2 cell with a cutoff voltage of 4.5 V further confirms the feasibility of high voltage electrochemistry in LiPF6-glyme ether electrolytes. These results clarify LiPF6-glyme ether interactions and offer new opportunities for designing advanced electrolytes for high-voltage LMBs.

Conspectus: The widespread adoption of graphene in commercial technology has long been hindered by the difficulty of producing high-quality material at scale and patterning it into functional circuits without complex, multistep lithography. This Account explores our laboratory’s solution to this challenge: the photothermal transformation of solution-processable graphene oxide (GO) into laser-scribed graphene (LSG). Unlike pristine graphene, which is difficult to disperse and pattern, GO is easily synthesized from bulk graphite and can be cast into uniform films on virtually any substrate via scalable solution-processing techniques. The transition from GO to LSG is significantly simplified through the use of a standard CO2 laser source. We observed that laser-scribed GO areas undergo highly effective reduction, characterized by a rapid expansion and exfoliation of the layers. This results in a film with exceptional conductivity and high porosity, yielding a remarkable surface area of 1520 m2 g–1. This reduction process fundamentally alters the chemical composition of the film, shifting it to a carbon content of 96.5% with a residual oxygen content of only 3.5%. Beyond pure carbon architectures, the core of our recent research focuses on the chemical diversification of the LSG library. After the first finding of laser-scribed graphene for supercapacitors, we found that by utilizing GO as a versatile host matrix, we have demonstrated that functional additives can be seamlessly integrated into the 3D graphene network during the scribing process. This Account will highlight our work from pure laser-scribed graphene to various materials with LSG as a host matrix, including laser-assisted lattice recovery of graphene by carbon nanodot incorporation, Si/LSG composites for high-capacity lithium-ion anodes, and the incorporation of VCl3 to create multivalent vanadium oxide/graphene hybrids for advanced sodium-ion batteries. These hybrid materials allow for precise tuning of the electrochemical and electronic properties of the resulting devices. We will detail how this laser-scribe approach enables the integration of these materials into multifunctional electronic systems. By bridging the gap between molecular-level carbon chemistry, heteroatom doping, and roll-to-roll manufacturing, LSG provides a blueprint for the future of wearable electronics and sustainable, integrated energy systems.

ConspectusPolyaniline, first discovered from coal tar over 150 years ago, is one of the most explored conducting polymers, due to its unique doping/dedoping chemistry, redox behavior, chemical stability, and simple synthesis. About 20 years ago, polyaniline nanofibers were developed through both interfacial polymerization and a rapid mixing method that produced high surface areas and aqueous dispersions, leading to versatile applications. Aniline oligomers, with much shorter and more well-defined chain lengths, gained great attention because they could offer more thorough insights into fundamental properties and perform precise molecular engineering for functionalization and modification. This Account summarizes our recent efforts to probing physical and chemical properties, crystal growth, catalytic effects, and applications of aniline oligomers.With a defined number of doping sites in the phenyl-capped aniline tetramer, we reveal the doping sequence by performing partial doping with characterization using electron paramagnetic resonance. Distinct from polyaniline, aniline tetramers can be dissolved in common organic solvents, thus offering an opportunity to observe the reduction through UV-vis spectroscopy. Acid reductions of the fully oxidized form, known as pernigraniline, were carried out at liquid/liquid and solid/vapor interfaces, as well as by using galvanic and piezoelectric reduction in solid-state reactions. Taking advantage of treating aniline oligomers as small molecules, we demonstrate the growth of organic single crystals through self-assembly. With various acids as dopants, a variety of nanostructured aniline oligomers with well-defined and hierarchical morphologies have been created. Furthermore, by adjustment of the molecule-solvent interactions, organic crystals of the aniline tetramer can be selectively grown on graphene substrates due to strong π-π stacking. The nucleation density, crystal size, and orientation of the organic crystals can be tuned using different solvents and infiltrating nonsolvents in an antisolvent crystallization process, providing an enhanced understanding of directional electrical conductivity in organic crystals. In the aniline polymerization process, it was realized that aniline oligomers serve as both nucleation sites and catalysts to produce ultralong and fibrillar morphologies. Through molecular engineering, the functionalization of the aniline tetramer with perfluorophenyl azide is demonstrated, rendering surface modifications of graphitic materials and antifouling and antibacterial ultrafiltration membranes via a simple UV light exposure. In addition, by covalently grafting aniline oligomers onto reduced graphene oxides and carbon nanotubes as the electrodes, supercapacitors with an ultralong cycle life─5 times longer than their polyaniline composite counterparts─are created. The superior cycling stabilities are due to the successful prevention of detachment of aniline oligomers and the preservation of the microstructure throughout the cycling process.With precise molecular structures and exceptional processability, we have found exciting properties and developed useful applications that outperform their polymer counterparts. Future research on aniline oligomers promises more discoveries of intriguing molecular science properties and practical applications with enhanced performances.

Aqueous sodium-ion batteries (SIBs) are gradually being recognized as viable solutions for large-scale energy storage because of their inherent safety as well as low cost. However, despite recent advancements in water-in-salt electrolyte technologies, the challenge of identifying anode materials with sufficient specific capacity persists, complicating the wider adoption of these batteries. This study introduces an innovative and straightforward approach for synthesizing vanadium oxide laser-scribed graphene (VO_x-LSG) composites, which function as effective anode materials in aqueous sodium-ion batteries. By combining a rapid laser-scribing technique with precise thermal control, the method not only allows for changing the morphology of the vanadium oxide, but also tuning its oxidation state. This is achieved while embedding these electrochemically active particles within a highly conductive graphene scaffold. When paired with a Prussian blue-based cathode (Na_1.88Mn[Fe(CN)₆]_0.97) in a concentrated NaClO₄-based aqueous electrolyte, the battery's charge storage mechanism is found to be largely surface-controlled, leading to exceptional rate performance. The full cell demonstrates specific capacities of 128 mA h/g@0.05 A/g and 65.6 mA h/g@1 A/g, with an energy density of 47.7 W h/kg, outperforming many existing aqueous sodium-ion batteries. This strategy offers a promising path forward for integrating efficient, eco-friendly, and low-cost anode materials into large energy storage devices and systems.

Lin and Kaner reflect on their group’;s Materials Horizons paper (Liao, Li and Kaner et al. , Mater. Horiz. , 2014, DOI: https://doi.org/10.1039/C3MH00049D) published in the journal and discuss how their work may have influenced the research field.

We report a novel synthetic approach combining laser-scribing and calcination to make a pseudocapacitive V ₂ O ₅ /laser-scribed graphene composite. The unconventional synthesis gives rise to high-performance.

Silicon has gained significant attention as a lithium‐ion battery anode material due to its high theoretical capacity compared to conventional graphite. Unfortunately, silicon anodes suffer from poor cycling performance caused by their extreme volume change during lithiation and de‐lithiation. Compositing silicon particles with 2D carbon materials, such as graphene, can help mitigate this problem. However, an unaddressed challenge remains: a simple, inexpensive synthesis of Si/graphene composites. Here, a one‐step laser‐scribing method is proposed as a straightforward, rapid (≈3 min), scalable, and less‐energy‐consuming (≈5 W for a few minutes under air) process to prepare Si/laser‐scribed graphene (LSG) composites. In this research, two types of Si particles, Si nanoparticles (SiNPs) and Si microparticles (SiMPs), are used. The rate performance is improved after laser scribing: SiNP/LSG retains 827.6 mAh g⁻¹at 2.0 A g_Si+C⁻¹, while SiNP/GO (before laser scribing) retains only 463.8 mAh g⁻¹. This can be attributed to the fast ion transport within the well‐exfoliated 3D graphene network formed by laser scribing. The cyclability is also improved: SiNP/LSG retains 88.3% capacity after 100 cycles at 2.0 A g_Si+C⁻¹, while SiNP/GO retains only 57.0%. The same trend is found for SiMPs: the SiMP/LSG shows better rate and cycling performance than SiMP/GO composites.

The macroscopic and microscopic interactions between liquid ammonia and graphitic materials are discussed, including dispersion, doping, mechanical testing, and shrinkages.