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Deoxyribonucleic acid (DNA)-based self-assembly has garnered considerable attention as a high-fidelity ‘bottom-up’ fabrication technique. Herein, intrigued by the amphiphilic nature of DNA molecules, we demonstrate a new class of DNA-directed amphiphilic self-assembly as a chemifunctional/multiscale-structuring strategy, beyond the previously reported DNA-mediated assemblies, and explore its potential application to lithium–sulfur (Li–S) batteries as a proof-of-concept. DNA-directed amphiphilic self-assembly enables the formation of various structures with a wide range of dimensional scales and exceptionally low bundle/junction electrical resistance, which are difficult to achieve with conventional DNA-mediated assemblies. The amphiphilic DNA molecules interact with single-walled carbon nanotubes (SWCNTs) through hydrophobic π–π stacking and divalent metal ions via electrostatic interaction. This results in electrically conductive DNA/SWCNT foams with hierarchical multiscale porous structures that can act as functional scaffolds of Li–S battery cathodes. Benefiting from the above-described advantageous effects, the DNA/SWCNT scaffold allows the resultant Li–S battery to provide significantly improved electrochemical performance. [ABSTRACT FROM AUTHOR]

Formidable challenges facing lithium-ion rechargeable batteries, which involve performance degradations and safety failures during charge/discharge cycling, mostly arise from electrode–electrolyte interface instability. Here, as a polymeric ionic liquid (PIL)-mediated interfacial control strategy to address this long-standing issue, we demonstrate a new class of molecularly designed, ion/electron-conductive nanoshields based on single-walled carbon nanotube (SWCNT)-embedded, dual-doped mesoporous carbon (referred to as “SMC”) shells for electrode materials. The SMC shell is formed on cathode materials through solution deposition of the SWCNT/PIL mixture and subsequent carbonization. The PIL (denoted as “PVIm[DS]”) synthesized in this study consists of poly(1-vinyl-3-ethylimidazolium) cations and dodecyl sulfate counter anions, whose molecular structures are rationally designed to achieve the following multiple functions: (i) precursor for the conformal/continuous nanothickness carbon shell, (ii) dual (N and S)-doping source, (iii) porogen for the mesoporous structure, and (iv) SWCNT dispersant. Driven by such chemical/structural uniqueness, the SMC shell prevents direct exposure of cathode materials to bulk liquid electrolytes while facilitating redox reaction kinetics. As a consequence, the SMC-coated cathode materials enable significant improvements in cell performance and also thermal stability. We envision that the SMC shell can be suggested as a new concept of effective and versatile surface modification strategy for next-generation high-performance electrode materials. [ABSTRACT FROM AUTHOR]

A solid-state electrolyte with reliable electrochemical performance, mechanical robustness and safety features is strongly pursued to facilitate the progress of flexible batteries. Here, we demonstrate a shape-deformable and thermally stable plastic crystal composite polymer electrolyte (denoted as "PC-CPE") as a new class of solid-state electrolyte to achieve this challenging goal. The PC-CPE is composed of UV (ultraviolet)-cured ethoxylated trimethylolpropane triacrylate (ETPTA) macromer/close-packed Al2O3 nanoparticles (acting as the mechanical framework) and succinonitrile-mediated plastic crystal electrolyte (serving as the ionic transport channel). This chemical/structural uniqueness of the PC-CPE brings remarkable improvement in mechanical flexibility and thermal stability, as compared to conventional carbonate-based liquid electrolytes that are fluidic and volatile. In addition, the PC-CPE precursor mixture (i.e., prior to UV irradiation) with well-adjusted rheological properties, via collaboration with a UV-assisted imprint lithography technique, produces the micropatterned PC-CPE with tunable dimensions. Notably, the cell incorporating the self-standing PC-CPE, which acts as a thermally stable electrolyte and also a separator membrane, maintains stable charge/discharge behavior even after exposure to thermal shock condition (=130 °C/0.5 h), while a control cell assembled with a carbonate-based liquid electrolyte and a polyethylene separator membrane loses electrochemical activity. [ABSTRACT FROM AUTHOR]

The first synthesis of a triphenylmethine (TM) library of compounds and screening of their Surface Enhanced Raman Scattering (SERS) capability was carried out to identify novel Raman reporters with high sensitivity. We identified three novel SERS reporters (B2, B7, and C7) with higher signal intensity than that of commonly used crystal violet (CV). These reporters may find potential applications in developing sensitive SERS based biosensors. [ABSTRACT FROM AUTHOR]