Deciphering Interphase Instability of Lithium Metal Batteries with Localized High-Concentration Electrolytes at Elevated Temperatures

Lithium metal batteries (LMBs), when coupled with a localized high-concentration electrolyte and a high-voltage nickel-rich cathode, offer a solution to the increasing demand for high energy density and long cycle life. However, the aggressive electrode chemistry poses safety risks to LMBs at higher temperatures and cutoff voltages. Here, we decipher the interphase instability in LHCE-based LMBs with a Ni0.8Co0.1Mn0.1O2 cathode at elevated temperatures. Our findings reveal that the generation of fluorine radicals in the electrolyte induces the solvent decomposition and consequent chain reactions, thereby reconstructing the cathode electrolyte interphase (CEI) and degrading battery cyclability. As further evidenced, introducing an acid scavenger of dimethoxydimethylsilane (DODSi) significantly boosts CEI stability with suppressed microcracking. A Ni0.8Co0.1Mn0.1O2||Li cell with this DODSi-functionalized LHCE achieves an unprecedented capacity retention of 93.0% after 100 cycles at 80 {\deg}C. This research provides insights into electrolyte engineering for practical LMBs with high safety under extreme temperatures.Comment: 10 pages, 8 figure

The application of ammonium polyphosphate in unsaturated polyester resins: A mini review

Ammonium polyphosphate (APP) is a common and commercially available flame retardant for various polymeric materials due to its low cost, ease of proccessing, low toxicity, and environmental friendliness. This mini review focuses on the application of APP in unsaturated polyester resin (UPR) and outlines the flame retardancy, thermal stability, and mechanical properties of the APP-containing UPR composites. As an effective acid source, APP can facilitate the dehydration and carbonization of the UPR matrix during combustion, forming a graphite char layer on the matrix surface to slow down heat exchange and volatile release, thus suppressing the burning reaction. Due to the inorganic properties of APP, microencapsulation and surface decoration are usually conducted on it to enhance its compatibility with UPR and its flame-retardant efficiency. Moreover, different flame-retardant synergists are also applied to strengthen the flame-retardant performance of APP in UPR. In this review, we briefly summarized the influences of microencapsulated APP, surface-decorated APP, and APP/synergist on the properties of UPR, respectively. Then, the advancement and challenges of these APP systems are highlighted, and future research opportunities are also proposed

Fire-retardant and high-strength polymeric materials enabled by supramolecular aggregates

High-performance polymers have proliferated in modern society across a variety of industries because of their low density, good chemical stability, and superior mechanical properties. However, while polymers are widely applied, frequent fire disasters induced by their intrinsic flammability have caused massive impacts on human beings, the economy, and the environment. Supramolecular chemistry has recently been intensively researched to provide fire retardancy for polymers via the physical barrier and char-catalyzing effects of supramolecular aggregates. In parallel, the noncovalent interactions between supramolecular and polymer chains, such as hydrogen bonding, π–π interactions, metal–ligand coordination, and synergistic interactions, can endow the matrix with enhanced mechanical strength. This makes it possible to integrate physical–chemical properties and noncovalent interactions into one supramolecular aggregate-based high-performance polymeric system on demand. However, fulfilling these promises needs more research. Here, we provide an overview of the latest research advances of fire-retardant and high-strength polymer materials based on supramolecular structures and interactions of aggregates. This work reviews their conceptual design, characterization, modification principles, performances, applications, and mechanisms. Finally, development challenges and perspectives on future research are also discussed

Engineering Ce/P-functionalized g-C3N4 for advanced ABS nanocomposites exhibiting unparalleled fire retardancy, enhanced thermal and mechanical properties

The nanomaterials have been deeply explored as flame retardants for various polymeric materials due to their multifunctionality, but they often fail to significantly increase the limiting oxygen index (LOI) and vertical burning UL-94 rating, thus unable to meet industrial needs (LOI>27.0 % and UL-94 V-0 rating). Herein, we fabricated a cerium/phosphorus-doped g-C3N4 (Ce/P-CN) nanohybrid as a multifunctional high-efficiency fire retardant for acrylonitrile–butadiene–styrene (ABS). The Ce/P-CN nanoflakes featured a strengthening effect towards ABS, 10 wt% of which increased the tensile strength of ABS/(Ce/P-CN) by 33.8 %. Meanwhile, the ABS/(Ce/P-CN) nanocomposites showed remarkably enhanced high-temperature stability and carbonization performances relative to virgin ABS. Ce/P-CN simultaneously improved the anti-ignition, fire retardancy and smoke suppression of ABS due to the barrier effect of g-C3N4 nanoflakes and the catalytic carbonization effect of cerium and phosphorus. Notably, adding 10 wt% Ce/P-CN increased the LOI and UL-94 rating of ABS to 28.6 % and V-0, respectively, demonstrating its high flame-retardant efficiency. Thus, the high flame-retardant efficiency and multifunctionality enable Ce/P-CN to outperform previous flame retardants for ABS. This work offers a novel strategy for the development of high-efficiency g-C3N4 nanoflakes, which endow ABS with improved mechanical robustness and fire retardancy and show broad industrial prospects

Structure–fire-retardant property correlations in biodegradable polymers

Because of widespread public concern about plastic waste treatment and recycling, there is a global trend toward replacing non-biodegradable polymers with biodegradable polymers. However, the inherent flammability of most biodegradable polymers presents a significant barrier to their potential application, necessitating the rapid development of fire-retardant biodegradable polymers. Herein, three major categories of fire retardants (FRs), including intrinsic FRs, additive FRs, and fire-retardant coatings, especially widely studied additive FRs in the categories of organic, inorganic, and inorganic–organic, are reviewed, revealing how the physical and chemical structures of FRs affect the fire-retardant efficiency of biodegradable polymers and concluding the influencing factors of their fire retardance from the perspective of the physical and chemical structures of FRs. This work provides fundamental data and mechanistic analyses for the fire-retardant parameters of biodegradable polymers by integrating/adding diverse types of FRs, to provide guidance for fabricating highly efficient fire-retardant biodegradable polymer materials and inspiring the development of future research and application of functional biodegradable polymers toward circular economy and greater sustainability

Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells

A Nonparametric Method for Automatic Denoising of Microseismic Data

Noise suppression or signal-to-noise ratio (SNR) enhancement is often desired for better processing results from a microseismic dataset. In this paper, we proposed a nonparametric automatic denoising algorithm for microseismic data. The method consists of three major steps: (1) applying a two-step AIC algorithm to pick P-wave arrival; (2) subtracting the noise power spectrum from the signal power spectrum; (3) recovering the microseismic signal by inverse Fourier transform. The proposed method is tested on synthetic datasets with different signal types and SNRs, as well as field datasets. The results of the proposed method are compared against ensemble empirical mode decomposition (EEMD) and wavelet denoising methods, which shows the effectiveness of the method for denoising and improving the SNR of microseismic data