Harbin University of Science & Technology

Aqueous zinc metal batteries (AZMBs) are promising candidates for renewable energy storage, yet their practical deployment in subzero environments remains challenging due to electrolyte freezing and dendritic growth. Although organic additives can enhance the antifreeze properties of electrolytes, their weak polarity diminishes ionic conductivity, and their flammability poses safety concerns, undermining the inherent advantages of aqueous systems. Herein, we present a cost-effective and highly stable Na2SO4 additive introduced into a Zn(ClO4)2-based electrolyte to create an organic-free antifreeze electrolyte. Through Raman spectroscopy, in situ optical microscopy, density functional theory computations, and molecular dynamics simulations, we demonstrate that Na+ ions improve low-temperature electrolyte performance and mitigate dendrite formation by regulating uniform Zn2+ deposition through preferential adsorption and electrostatic interactions. As a result, the Zn||Zn cells using this electrolyte achieve a remarkable cycling life of 360 h at − 40 °C with 61% depth of discharge, and the Zn||PANI cells retained an ultrahigh capacity retention of 91% even after 8000 charge/discharge cycles at − 40 °C. This work proposes a cost-effective and practical approach for enhancing the long-term operational stability of AZMBs in low-temperature environments.

The development of advanced polymer dielectrics for electronic and energy storage devices demands precise nanoscale molecular design. Departing from conventional strategies that merely augment free volume fraction, this study proposes a robust approach to optimize dielectric performance by homogenizing nanoscale free volume distribution via a tailored micro-branched architecture. Maleic anhydride-capped HDI trimer (HM) and TDI trimer (TM) were chemically grafted into a bismaleimide (BMI) resin to construct a micro-branched polymeric network with well-defined nanoscale topology. Positron annihilation lifetime spectroscopy (PALS) and molecular dynamics simulations collectively confirm that the optimized micro-branched structure enables a homogeneous distribution of nanoscale free volume holes (radius reduced to 0.256 nm), which efficiently restricts the mean free path of charge carriers through a prominent nanoscale confinement effect. Synergistically with the enhanced crosslinking density derived from the branched architecture, this nanoscale engineering strategy yields extraordinary dielectric performance: the breakdown strength is drastically enhanced by 48.2% to 35.62 kV/mm, the relative permittivity is reduced to 2.90, and the glass transition temperature is significantly elevated. Complementary theoretical calculations further verify that the micro-branched units reinforce electron-trapping capability at the nanoscale. This work establishes a versatile nanoscale design strategy for advanced polymer dielectrics, emphasizing the importance of precise free volume engineering at the molecular-nanoscale interface. The findings hold broad prospects for advancing the application of high-performance dielectric materials in nanodevices, flexible electronics, and high energy density storage systems.

The widespread use of pentachloronitrobenzene (PCNB) poses a serious threat to environment and human health, making its precise detection in agricultural products and food samples crucial. In this study, a triphenylamine-based fluorescent probe TP was proposed and designed for the selective and accurate quantitative detection of PCNB. Probe TP combined a triphenylamine fluorescent group with an anthracene-based unit, which enabled a significant extension of the conjugation system and an enhanced π-π interaction, achieved specific recognition of PCNB based on intermolecular forces while maintaining the optical activity of the fluorophore. During the detection process, probe TP exhibited a low limit of detection (LOD) of 19 nM and showed remarkable selectivity for PCNB over other common pesticides widely used in agricultural activities, and demonstrated high accuracy in real herbal samples, nutraceuticals and vegetables, achieved spiked recoveries of 95.00% ∼ 103.75%. In addition, probe TP showed low cytotoxicity and cell membrane permeability, enabling imaging of PCNB-induced cells, was expected to serve as an interdisciplinary-integrated molecular tool for PCNB detection.