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High energy and power density alkali‐ion (i.e., Li+, Na+, and K+) batteries (AIBs), especially lithium‐ion batteries (LIBs), are being ubiquitously used for both large‐ and small‐scale energy storage, and powering electric vehicles and electronics. However, the increasing LIB‐triggered fires due to thermal runaways have continued to cause significant injuries and casualties as well as enormous economic losses. For this reason, to date, great efforts have been made to create reliable fire‐safe AIBs through advanced materials design, thermal management, and fire safety characterization. In this review, the recent progress is highlighted in the battery design for better thermal stability and electrochemical performance, and state‐of‐the‐art fire safety evaluation methods. The key challenges are also presented associated with the existing materials design, thermal management, and fire safety evaluation of AIBs. Future research opportunities are also proposed for the creation of next‐generation fire‐safe batteries to ensure their reliability in practical applications. [ABSTRACT FROM AUTHOR]

Frequent fire disasters have caused massive impacts to the environment, human beings, and the economy. MXene has recently been intensively researched as potential flame retardants to provide passive fire protection for other materials via its physical barrier and catalyzing carbonization effects. In parallel, MXene has also demonstrated a great promise for creating early fire warning sensors, which is an emerging field that has the potential to provide active fire response through its thermoelectric effect. This makes it possible to integrate passive fire retardancy and active fire warning into one MXene‐based fire protection system on demand. However, fulfilling these promises needs more research. Herein, an overview of passive flame‐retardant materials and next‐generation smart fire warning materials/sensors based on MXene and its derivatives is provided. This study reviews their conceptual design, characterization, modification principles, performances, applications, and mechanisms. A discussion of the challenges that need to be solved for their future practical applications and opportunities is also presented. [ABSTRACT FROM AUTHOR]

A solvent-free green approach has been developed to synthesize a Si-containing polyphosphoramide (DM-Si) for creating transparent and fire-retardant PLA materials. [Display omitted] • A green strategy for a Si-containing polyphosphoramide (DM-Si) was developed. • 1 wt% DM-Si significantly improves the fire safety of PLA. • The toughness of PLA increases to 4.7 MJ/m2 but maintaining its tensile strength. • The transparency of PLA fire-retardant composites is well-preserved. Renewable polylactide (PLA) features good biodegradability, high optical transparency and mechanical strength. However, inherent flammability severely restricts its practical applications in packaging, fabric and electronics. Polyphosphoramides have recently demonstrated high fire-retardant effectiveness in PLA, but their synthesis usually involves the use of a large volume of toxic organic solvents, in addition to their negative impacts on the transparency of PLA. Herein, we report a one-pot green solvent-free approach for massively synthesizing a silicon (Si)-containing polyphosphoramide (DM-Si). The results show that with only 1.0 wt% of DM-Si, the resultant PLA material exhibits desirable fire retardancy, e.g., a UL-94 V-0 rating and a limiting oxygen index of 27.9%, and a 68% increase in toughness relative to virgin PLA. Moreover, both the tensile strength and transparency of PLA are well-preserved. This work provides an eco-benign yet facile strategy for the synthesis of efficient flame retardants for bioplastics with balanced mechanical strength and transparency, which hold great promise as sustainable materials for many industrial applications. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is a fatal complication of diabetes and the main cause of end-stage renal disease. Due to the suboptimal effects of current treatments, there is an urgent need to develop new therapeutic strategies for DN. Trametenolic acid (TA), a lanostane-type tetracyclic triterpenoid, is one of the main active ingredients extracted from the natural product Inonotus obliquus. Our study was aimed at clarifying the potential protective effects of TA on DN and its underlying mechanism. In this research, C57BLKS/db (db/db) mice were used as the spontaneous DN model, and TA (10 mg/kg/d) was intraperitoneally injected for 4 consecutive weeks. Ratio of right kidney weight/body weight was calculated, and the contents of serum creatinine (Scr), blood urea nitrogen (BUN), and urine albumin were detected. The activities of superoxide dismutase (SOD) and catalase (CAT) and the contents of reductive glutathione (GSH) and malondialdehyde (MDA) were measured. The histopathological changes of renal tissues were observed by hematoxylin and eosin (HE), periodic acid-Schiff (PAS), and Masson staining. The protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase-1 (NQO-1), nuclear factor kappa B (NF-κB), proinflammation cytokine tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), Nephrin, and Podocin were detected by western blot assay. Immunohistochemistry was utilized to detect expressions of collagen III (COL-III) and fibronectin (FN). Our results showed that TA administration significantly reduced the ratio of right kidney weight/body weight, BUN, Scr, and urine albumin levels and alleviated the histopathological changes of DN mice. Moreover, TA administration remarkably increased GSH content and SOD and CAT activities and decreased MDA content. Western blot assay demonstrated that TA activated Nrf2 signaling and increased the expression of downstream antioxidant enzymes HO-1 and NQO-1. Further studies illustrated that NF-κB signaling was inhibited, and downstream proinflammation cytokine expressions of TNF-α, IL-6, and IL-1β were also downregulated. In addition, we also found that TA administration significantly increased the expression of nephrin and podocin proteins and reduced the protein expression of COL-III and FN. These findings suggested that TA exhibited a renoprotective effect by ameliorating oxidative stress and inflammation via Nrf2/HO-1 and NF-κB signaling pathways. [ABSTRACT FROM AUTHOR]

• Novel layered MXene-PPDA-6 was rationally designed and synthesized. • The addition of 1.0 wt% of MXene-PPDA-6 hybrid significantly increases both thermal stability and flame retardancy of PLA. • The MXene-PPDA-6 hybrid can improve the toughness of PLA. The creation of thermostable, flame-retardant, mechanically robust bioplastics is highly desirable in the industry as one sustainable alternative to traditional petroleum-based plastics. Unfortunately, to date there lacks an effective strategy to endow commercial bioplastics, such as polylactide (PLA) with such desired integrated performances. Herein, we have demonstrated the fabrication of a novel MXene-phenyl phosphonic diaminohexane (MXene-PPDA) nanohybrid via the intercalation of PPDA into the MXene interlayer. The interlayer spacing of MXene nanosheets is enlarged and as-prepared MXene-PPDA is homogeneously dispersed in the PLA matrix. Incorporating 1.0 wt% MXene-PPDA enables PLA to achieve a UL-94 V-0 rating, with a ~22.2% reduction in peak heat release rate, indicating a significantly improved flame retardancy. Meanwhile, the 1.0 wt% MXene-PPDA also increases the initial decomposition temperature of PLA composite, giving rise to a ~25-fold enhancement in char yield relative to pure PLA. Additionally, the MXene-PPDA enhances the toughness while retains the mechanical strength for PLA. This work offers an innovative strategy for the design of multifunctional additives and the creation of high-performance polymers with high thermal stability, mechanical robustness and low flammability, expecting to find many practical applications in the industry. [ABSTRACT FROM AUTHOR]

Biodegradable polymeric materials with high strength and outstanding toughness are necessary for real‐world applications in the fields of electronics, electrics, and packaging. Unfortunately, such performance portfolios in polymers remain challenging to achieve due to their different governing mechanisms. Inspired by the hydrogen‐bond (H‐bond) cross‐linking structure of spider silk, herein, strong and tough poly(vinyl alcohol) (PVA) composites with β‐cyclodextrin as a cross‐linker are developed. Benefiting from the H‐bond cross‐linking effect, the addition of 1.0 wt% of β‐cyclodextrin enables PVA to achieve a high tensile strength of 136.5 MPa, and a high elastic modulus of 3.0 GPa, in combination with a good toughness of 82.1 MJ m−3. In addition, the presence of β‐cyclodextrin improves the biodegradability of PVA composite by decreasing its crystalline size. Furthermore, PVA/β‐cyclodextrin composite combined with MXene has great potential as a sensor material for humidity and strain detection. This proof‐of‐concept opens numerous opportunities to create strong, tough, and biodegradable polymers for packing and sensing applications. [ABSTRACT FROM AUTHOR]

Phosphoramides, as a kind of high-efficient fire retardants, have been designed in many structures and endowed exceptional fire retardancy to polylactide (PLA). However, due to ignorance of the structure-property correlation, the effect of phosphoramides' structure on the fire retardancy and mechanical properties of PLA is still unclear. Herein, a series of biobased phosphoramides (phosphoramide (V1), linear polyphosphoramide (V2) and hyperbranched polyphosphamide (V3)) were designed and incorporated into PLA, and the structural effect of phosphoramides on the fire-retardant and mechanical properties of PLA was deeply researched. Among three kinds of phosphoramides, the hyperbranched polyphosphoramide is more effective than the corresponding linear polyphosphoramide and phosphoramide in improving the fire-retardant and anti-dripping properties of PLA, and only linear polyphosphoramide shows a positive effect in the mechanical strength of PLA. This work provides a feasible strategy for creating mechanically robust and fire-retardant polymer composites by molecularly tailoring the structure of fire retardants and uncovering their structure-property relationship. [Display omitted] • The structure-property correlation of PLA/phosphoramides was unveiled. • Hyperbranched polyphosphoramide shows the best performance in fire retardancy and anti-dripping behaviors of PLA. • Linear polyphosphoramide can simultaneously improve the tensile strength, elastic modulus and fire retardancy of PLA. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bioderived Schiff base containing polyphosphonate (PVP) was rationally synthesized. • As-developed PVP has a high biomass content of 72% by mass. • The addition of only 0.5 wt% of PVP can lead to exceptional fire retardancy of PLA. • PVP can increase the mechanical strength of PLA as compared to pure PLA. To expand the practical application and realize sustainable development, it is urgent to develop advanced polylactide composites with fire retardancy and mechanically strong properties by utilizing bio-derived additives. Unfortunately, such desired performance portfolio is still unsatisfactory due to unclear mechanism and improper design strategy. In this paper, a novel bio-derived polyphosphonate containing Schiff base (PVP) was prepared by a two-step method of condensation and addition reactions. By incorporating only 0.5 wt% PVP, the LOI value of PLA is increased to 32.5 vol% as well as achieving a UL-94 V-0 rating. Such superior fire retardancy is ascribed to the physical barrier effect of char residue, which arising from the cyclization of Schiff base and catalytic carbonization of polyphosphonate. Due to the crosslinking reaction between PLA and PVP and nucleating effect of PVP in the PLA matrix, the mechanical strength of PLA is increased by 10.2% with addition of 1.0 wt% PVP. This study provides a feasible way for designing bio-derived fire retardants to simultaneously improving the fire retardancy and mechanical strength of PLA, thus is expected to expand the practical application of PLA materials. [ABSTRACT FROM AUTHOR]

Despite good biodegradability and mechanical strength, the intrinsic flammability of poly(L-lactic acid) (PLA) impede its practical application. Introducing phosphoramide is an effective method to enhance the flame retardancy of PLA. However, most of the reported phosphoramides derive from petroleum resources, and their addition tends to deteriorate the mechanical properties, especially toughness, of PLA. Herein, a bio-based, furan-containing polyphosphoramide (DFDP) with high flame-retardant efficiency was synthesized for PLA. Our study found that 2 wt% DFDP enabled PLA to pass a UL-94 V-0 rating, and 4 wt% DFDP increased the limiting oxygen index (LOI) to 30.8 %. DFDP effectively maintained the mechanical strength and toughness of PLA. The tensile strength of PLA with 2 wt% DFDP reached 59.9 MPa, and its elongation at break and impact strength were increased by 15.8 % and 34.3 %, respectively, relative to those of virgin PLA. The UV protection of PLA was significantly enhanced by introducing DFDP. Hence, this work provides a sustainable and comprehensive strategy for the creation of flame-retardant biomaterials with improved UV protection and well-preserved mechanical properties, which possess a broad prospect in industrial application. [ABSTRACT FROM AUTHOR]

• Multifunctional nanohybrid (FeHP@GO) has been prepared via a facile and scalable approach. • Adding 1 wt% FeHP@GO significantly improves fire retardancy and mechanical properties of EP. • The EP/FeHP@GO sample shows superior flame retardancy and mechanical property to previous work. • The thermal conductivity of EP/FeHP@GO nanocomposites are also dramatically improved. The epoxy (EP) resin is being intensively applied in electronics packaging, the 5th generation communication technology (5G) and composite tanks for pressurized hydrogen fuel storage. For these applications, to date it has remained a grand challenge for EP to achieve a demanding property portfolio, e.g., the combination of satisfactory fire retardancy, high thermal conductivity (λ) and excellent mechanical properties. Herein, we report an iron phenylphosphinate-functionalized graphene oxide (FeHP@GO) nanohybrid by a facile yet scalable in-situ self-assembly method. Compared to the virgin EP, the EP nanocomposite with 2.0 wt% of FeHP@GO shows 42.5 % improvement in the limiting oxygen index (LOI), 46.2 % and 23.5 % reductions in the peak heat release rate (PHRR) and total heat release rate (THR), respectively, and a desired UL-94 V-0 rating. In addition, the resultant EP nanocomposite also exhibits improved tensile strength and λ (increased by 32.6 % and 96.0 %, respectively) relative to virgin EP. Such desirable integrated performances outperform those of the previously-reported EP counterparts, because of the multiple synergistic effects between FeHP and GO. This work provides an innovative strategy for the design of multifunctional EP nanocomposites, which holds the great promise for many industrial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional P/Ni-doped g-C 3 N 4 (Ni-P-C 3 N 4) nanoflakes were synthesized. • Ni-P-C 3 N 4 can be homogeneously dispersed in ABS by simple melt-blending. • Ni-P-C 3 N 4 endowed ABS with enhanced thermal stability and mechanical strength. • Ni-P-C 3 N 4 significantly improved the flame retardancy and smoke suppression of ABS. The ubiquitous application of highly flammable acrylonitrile–butadienestyrene (ABS) resin has brought great fire threat to human and environment. Unfortunately, current flame retardants often improve flame retardancy but reduce mechanical and thermal properties, seriously affecting their practical application. We herein reported novel multifunctional, high-efficiency, phosphorus and nickel co-doped graphitic carbon nitride (Ni-P-C 3 N 4) nanoflakes to address the trade-off between flame retardancy and mechanical/thermal properties. The addition of 2.0wt% of Ni-P-C 3 N 4 increased the initial degradation temperature and tensile strength of ABS composite (ABS/Ni-P-CN2) by 15 °C and 24.3% relative to virgin ABS, indicating its positive effect on thermal and mechanical properties. Compared with ABS, ABS/Ni-P-CN2 exhibited a notable increase in time to ignition, along with 32.4% and 33.8% reductions in peak heat release rate (PHRR) and peak smoke production rate (PSPR), demonstrating excellent anti-ignition, flame-retardant and smoke-suppressive performances. The increased fire safety was mainly due to the physical barrier effect of g-C 3 N 4 nanosheets and the catalytic charring effect of P and Ni. This work offers a novel design strategy to create multifunctional flame retardants for fabricating fire-safe polymer composites with superior thermal and mechanical properties, holding great potential in industries. [ABSTRACT FROM AUTHOR]