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Graphite anode materials and carbonate electrolyte have been the top choices for commercial lithium-ion batteries (LIBS) for a long time. However, the uneven deposition and stripping of lithium cause irreversible damage to the graphite structure, and the low flash point and high flammability of the carbonate electrolyte pose a significant fire safety risk. Here, we proposed a multifunctional electrolyte additive diphenylphosphoryl azide (DPPA), which can construct a solid electrolyte interphase (SEI) with high ionic conductivity lithium nitride (Li3N) to ensure efficient transport of Li+. This not only protects the artificial graphite (AG) electrode but also inhibits lithium dendrites to achieve excellent electrochemical performance. Meanwhile, the LIBS with DPPA offers satisfactory flame retardancy performance. The AG//Li half cells with DPPA-0.5M can still maintain a specific capacity of about 350 mAh/g after 200 cycles at 0.2 C. Its cycle performance and rate performance were better than commercial electrolyte (EC/DMC). After cycling, the microstructure surface of the AG electrode was complete and flat, and the surface of the lithium metal electrode had fewer lithium dendrites. Importantly, we found that the pouch cell with DPPA-0.5M had low peak heat release rate. When exposed to external conditions of continuous heating, DPPA significantly improved the fire safety of the LIBS. The research of DPPA in lithium electrolyte is a step towards the development of safe and efficient lithium batteries. [ABSTRACT FROM AUTHOR]

Polymer composites exhibiting exceptional characteristics, including high thermal conductivity, thermal stability, mechanical strength, and flame resistance, offer significant potential for contemporary electronic applications. Their appeal is further heightened by features such as straightforward manufacturing processes, cost-effectiveness, and consistent physical and chemical properties. In this study, a bio-derived ligand was synthesized from vanillin through a Schiff base reaction. Subsequently, this ligand was employed in the synthesis of a silver complex (Ag-complex) through a Schiff base ligand-mediated process designed to extract silver ions from a wastewater stream. Moreover, the Ag-complex served as an additive to enhance the flame resistance and amplify the thermal conductivity of an epoxy resin (EP). The results from thermogravimetric analysis (TGA) revealed that the Ag-complex promoted the formation of char in the EP composites. Specifically, the EP composite containing 20.0 wt% of the Ag-complex exhibited a significantly increased limiting oxygen index (LOI) of 27.0%, and demonstrated improved thermal conductivity. Additionally, this composite showed a substantial reduction (47.84%) in heat release rate (HRR), a noteworthy decrease of 45.16% in total heat release (THR), and a marked decline in smoke production rate (SPR) by 26.15%, along with reductions in CO production rate (52.34%) and CO 2 production rate (29.53%). Furthermore, the EP composite containing 20.0 wt% of the Ag-complex displayed superior tensile strength compared to the unmodified EP. This research introduces an innovative approach for developing fire-resistant EP with enhanced thermal conductivity, achieved by repurposing waste materials derived from water decontamination adsorbents. • A Schiff base ligand derived from vanillin was produced. • An Ag-complex was formulated by extracting silver ions from wastewater using the Schiff base ligand. • The HRR of the EP-Ag-complex-20wt% decreased by 47.8% when compared to that of the pristine EP. • The SPR of the EP-Ag-complex-20wt% decreased by 26.1% in comparison to that of the pristine EP. • The addition of 20wt% of the Ag-complex significantly enhanced the thermal conductivity of the EP composite. [ABSTRACT FROM AUTHOR]

In this work, microcrystalline cellulose (MCC) treated polyamide 66 (PA66) textiles were coated with green and naturally abundant polysaccharides specifically, chitosan (CS) and sodium alginate (SA) together with phytic acid (PA) via layer by layer (LbL) deposition. The prime focus of such treatment was to intensify both the hydrophilic and flame retardant properties of PA66 fabric substrates. Subsequently, the prepared coatings were further subjected to cross-linking modification by dipping them into the barium (Ba) salt solution. Obtained results indicated that the MCC-modified PA66 exhibited a water contact angle (WCA) value of 00 and revealed a drop in peak heat release rate (pHRR) up to 31 % with complete suppression of melt-dripping. Meanwhile, the Ba-ion-induced cross-linking treatment further escalated this reduction up to 36 % by adding enhanced thermal stability, improved char quality along better wash durability of as prepared coatings. In addition, the combined modification of PA66 textiles with MCC and Ba-ion handed a superb enhancement of physical properties like tensile strength by ca. 50 % compared to the pure PA66. Thus, this MCC-assisted surface modification paves the way for a new kind of greener treatment of PA66 textiles in attaining superior hydrophilic and flame retardant properties of the same. • MCC-assisted surface engineering of PA66 fabrics was done. • Green polysaccharides were deposited on PA66 surfaces in LbL assembly. • MCC-modified and LbL deposited fabric surfaces exhibited superhydrophilicity. • MCC-modified and LbL deposited showed a substantial reduction in pHHR by 36 %. • Ba ion cross-linking helped to obtain superior wash durability to developed coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A core-shell structured piperazine pyrophosphate microcapsules (MT@PAPP) is constructed. • The MT@PAPP enhances the compatibility and mechanical property of TPE/MT@PAPP composites. • Compared with pure TPE, the PHRR and PSPR of TPE/MT@PAPP were reduced by 78.5% and 60.0%, respectively. In this study, core-shell structured piperazine pyrophosphate (PAPP) is designed to enhance the fire safety and mechanical property of styrenic thermoplastic elastomer (TPE) composites. The PAPP is microencapsulated with carbon nanotube modified melamine-formaldehyde resin to prepare core-shell structured flame retardants (MT@PAPP). Due to the excellent compatibility between the MT@PAPP and TPE matrix, the mechanical property of TPE/MT@PAPP is improved. Compared with TPE, the peak heat release rate and peak smoke production rate of TPE/MT@PAPP are decreased by 78.5% and 60.0%, respectively. Thus, the core-shell structured piperazine pyrophosphate microcapsule strategy provides an excellent approach to obtain high-performance TPE composites. [ABSTRACT FROM AUTHOR]

• Intrinsically flame-retardant hydrogel coatings for RPUFs were developed to reduce their flammability. • RPUF composites achieved a 45% reduction in the TSP, a 27 s increase in the TTI and excellent coating adhesion. • Fire-resistant hydrogels were constructed by combining a multiscale reinforcement strategy and a flame-retardant precursor. Hydrogel, as a multifunctional engineering material, has attracted much attention for its flame-retardant applications. However, the low thermal stability of hydrogels results in the formation of a weak protective layer with weak adhesion, which limits their application. Therefore, through careful design, we successfully combined calcium phosphate nanocrosslinked points, silica nanofiber networks, and black phosphorus sheets to construct a multiscale reinforcing body. This reinforcement not only significantly improves the overall strength of the material, but also imparts excellent fire resistance properties. Furthermore, we combined this reinforcement with intrinsic flame-retardant precursors to construct a hydrogel with high fire resistance. This hydrogel coating not only effectively resists flame attacks, but also exhibits excellent mechanical properties, thus addressing the shortcomings of conventional hydrogel coatings in terms of fire resistance and mechanical properties. When used to coat RPUF materials, the hydrogel-coated RPUF composites showed a 23.6% reduction in the peak heat release rate (pHRR), a 45% reduction in total smoke production (TSP), and a 27 s extension in time to ignition (TTI). The hydrogel coating was found to be effective at inhibiting the spread of fire. In addition, the molecularly designed intrinsic flame-retardant hydrogel coating has good adhesion to RPUF and other substrates, which is sufficient for practical applications. The coatings have sustained fire protection and are suitable for a range of flame-retardant applications. This innovative design provides new ideas and methods for developing high-performance flame-retardant hydrogel coatings. [ABSTRACT FROM AUTHOR]

• A series of coatings with high transparency and excellent pencil hardness levels were prepared on polycarbonate (PC) substrates via a two-step UV-curing process with TAEP and MAAR. • The coupling effect of the combustion behaviours of the UV-cured coatings and the PC substrates was particularly investigated to give insight into a holistic picture of the combustion of the coated PC composites. • The composite UV-cured coatings successfully suppressed the heat release and improved the flame retardancy of the PC samples thanks to the phosphorus-nitrogen synergistic flame-retardant effect in the condensed phase. • A potential strategy to further enhance the flame-retardant ability of the UV-cured coatings lies in improving the thermal and mechanical stabilities of the intumescent char layers. There is an urgent demand for flame retardant treatment of polycarbonate (PC) with as little adverse impact on the inherent advantages of PC as possible, especially the high transparency. Herein, a flame-retardant coating with high transparency was successfully prepared on PC via a two-step ultraviolet-curing (UV-curing) process with tri(acryloyloxyethyl) phosphate and melamine acrylate resin. All the coated PC composites showed high transparency and excellent pencil hardness levels (6H). The coupling effect of the combustion behaviours of the UV-cured coatings and the PC substrates was particularly investigated to give insight into a holistic picture of the combustion of the coated composite systems. Specifically, all the composite UV-cured coating samples (T2M1, T1M1 and T1M2) formed highly expanded char with honeycomb-like inner structure due to the phosphorus-nitrogen synergistic effects, which could efficiently suppress mass and heat transfer, thereby protecting the PC substrates from the harsh conditions of high temperature and realizing significantly enhanced flame retardancy of the PC samples. Improving the thermal and mechanical stabilities of the intumescent carbon layers may be a practical strategy to achieve further improved flame retardant capabilities of the PC samples. Additionally, the PC-T2M1 composite exhibited the optimal flame retardant effect, realizing significantly suppressed heat release in the cone calorimeter tests, reaching UL94 V-0 rating and showing long fire resistance time thanks to the intumescent char. The UV-cured coating method introduced in this work had great potential in spawning new strategies for designing advanced flame retardant coatings for polymer substrates. [Display omitted] [ABSTRACT FROM AUTHOR]

A synergistic flame retardant with a core-shell structure utilizes the 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative as the outer shell and ammonium polyphosphate (APP) as the inner core. Three derivatives of DOPO (DOPO-GY, DOPO-DH and DOPO-GD) are synthesized by reacting DOPO with glyoxal, paraformaldehyde and diethanolamine, and glutaraldehyde, respectively. DOPO-GY@APP, DOPO-DH@APP and DOPO-GD@APP exhibit good radical scavenging activities. The oxidation induction time for EVA/DOPO-GY@APP is exceptionally high at 19.04 min, in contrast to EVA alone, which has an induction time of only 5.51 min. Simultaneously, after aging at 180 °C and 165 °C for 7 days, the retention rates of elongation at break for EVA/DOPO-GY@APP are 34.67 % and 55.50 %, respectively. These findings demonstrate the long-term anti-aging properties of EVA/DOPO-GY@APP without the need for additional antioxidants. Moreover, EVA/DOPO-GY@APP, EVA/DOPO-DH@APP and EVA/DOPO-GD@APP all achieve V-0 rating with 25 % addition of flame retardant. In comparison to pure EVA, their peak heat release rates and maximum smoke density decrease by 52 % and 47 %, 43 % and 54 %, and 51 % and 44 %, respectively. Additionally, compared to EVA/APP, their mechanical properties have been improved. Therefore, these microencapsulated flame retardants with DOPO derivatives as the shell effectively enhance the mechanical properties and fire safety of EVA composites. [Display omitted] • A multifunctional microencapsulated flame retardant is successfully designed. • The DOPO-GY@APP shows good radical scavenging activities. • The retention rate of EB from EVA/DOPO-GY@APP can reach 55.50 % after aging at 165 °C for 7 days. • EVA/DOPO-GY@APP reveal anti-aging properties without adding any antioxidant. • The pHRR and Ds max of EVA/DOPO-GY@APP are reduced by 52 % and 47 %, respectively. [ABSTRACT FROM AUTHOR]

• An organic-inorganic hybrid flame retardant (THPSU-MMT) was synthesized. • EP-MMT composites have good flame retardancy and comprehensive properties. • The thermal decomposition of EP-MMT composites was studied. • It provides a green and efficient method for exfoliation of montmorillonite. Traditional additive flame retardants pose issues including high dosage, easy precipitation, and poor compatibility with the matrix. Designing efficient organic-inorganic synergistic flame retardants can enhance the flame retardancy and mechanical properties of epoxy (EP) composites while reducing their smoke toxicity. In our study, we initially employed Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) for intercalation modification of montmorillonite (MMT). Subsequently, we achieved a green and efficient exfoliation of MMT by reacting urea with hydroxyl groups, resulting in the simultaneous preparation of efficient organic/inorganic synergistic flame retardants (THPSU-MMT). EP composites containing 5wt% THPSU-MMT can attain UL-94 V0 classification. Furthermore, the peak heat release rate (PHRR), total heat release (THR), and peak release rates of CO can be reduced by up to 78.42 %, 62.26 %, and 72.50 %, respectively. Simultaneously, we systematically investigated the synergistic flame retardant mechanism of the EP composite. The findings reveal that THPSU-MMT exhibits a dual flame retardant effect in both the gaseous and condensed phases. Moreover, the combination of MMT and THPSU substantially enhances the presence of phosphorus-containing pyrolysis products in the condensed phase. The fire performance index (FPI) of the flame retardant EP increased from 0.05 m2/s/W in pure EP to 0.36 m2/s/W, attributed to the enhanced catalytic carbonization and assisted gas-phase free radical capture. Additionally, the flame spread index (FGI) decreased from 11.55 kW/m/s in pure EP to 1.18 kW/m/s, signifying a substantial enhancement in fire safety. Furthermore, the THPSU-MMT synergistic flame retardants improved the tensile strength of EP composites. This study offers an environmentally friendly and efficient approach for the effective exfoliation of MMT, while also presenting novel concepts for the design of efficient organic-inorganic synergistic flame retardants. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The free switch of passive radiation cooling and solar thermal conversion is realized. • An average temperature drop of ∼5.62 °C is achieved under the hot environment. • A temperature increase of 28.3 °C is achieved under the cold environment. • The fire hazards of materials designed are suppressed significantly. Seasonable and spontaneous replacement approach of daytime radiative cooling to solar thermal conversion is challenging yet imperative for year-round thermal management materials. Meanwhile, the fire safety of thermal management materials is extremely important but often overlooked. Herein, we report a bio-inspired and fireproof aerogel presenting dynamically self-switchable ability of daytime radiative cooling and solar thermal conversion, composed of thermochromic microcapsules (TC), boron nitride nanosheets (BN), and bio-based materials (alginate and phytate). In hot environments, TC/BN composite aerogel shows solar reflectivity of 91.8 % and IR emissivity of 84.3 %, promoting heat radiation to outer space and achieving an average temperature drop of ∼5.62 °C. Attributed to the thermochromic mechanism, TC/BN composite aerogel can harvest visible light of 87 % in the solar spectrum to increase the material temperature by 28.3 °C, under an environment of −8.8 °C. Based on the EnergyPlus simulation, the employment of TC/BN composite aerogel contributes to decreasing the energy consumption of buildings in both hot and cold regions, including Cairo, Singapore, Alaska, Yakutsk, and so on. Besides, the peak values of heat release rate and total heat release during the combustion of TC/BN composite aerogels are significantly decreased by 70.6 % and 58.4 %, compared to those of TC composite aerogel. The produced protective char layer enhanced by BN nanosheets is capable of isolating the fire and suppressing the fire propagation, improving the fire safety of composite aerogels designed. The TC/BN composite aerogels provide a smart thermal regulation mode for radiative cooling and solar heating, overcome the problems from changing weather and environment, and significantly promote the practical application by enhanced fire safety. [ABSTRACT FROM AUTHOR]

Epoxy resin (EP) is quite flammable, which limits its application in areas such as coatings and electronic and electrical materials. In this study, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (or diphenylphosphine oxide (DPO)) 3-cyclohexene-1-formaldehyde (CC) and 4,4'diaminodiphenylmethane (DDM) were selected for the synthesis of two rich aromatic and phosphorus-containing compounds (DOPO-CC and DPO-CC). DOPO-CC and DPO-CC were introduced into epoxy pre-polymers to prepare epoxy thermosets with flame retardancy. When 5 wt% DOPO-CC (P content of 0.50 wt%) or DPO-CC (P content of 0.52 wt%) was added, the LOI values of the epoxy thermosets increased from 25.5% (pure EP) to 33.5% (EP added DOPO-CC) and 31.0% (EP added DPO-CC), respectively, and these epoxy thermosets also achieved the UL-94 V-0 rating. Additionally, cone calorimeter tests showed that the peak heat release rate (PHRR) and total heat release (THR) of epoxy thermoset containing 5 wt% DPO-CC reduced by 42.0% and 39.7% compared to those of pure EP, respectively. By reducing the thermal degradation rate (condensed phase) and combining and quenching free radicals (gaseous phase), the introduction of DOPO-CC or DPO-CC can efficiently improve the flame retardancy of epoxy thermosets. More importantly, the epoxy thermosets containing DOPO-CC or DPO-CC exhibited better mechanical properties than pure EP, which could be proven by the storage modulus and tensile strength. This study provided a new class of rich aromatic and phosphorus-containing compounds that can serve as co-curing agents for epoxy thermosets with outstanding comprehensive performances. [Display omitted] • Two rich aromatic and phosphorus-containing compounds (DOPO-CC and DPO-CC) were synthesized. • EP containing 5 wt% DOPO-CC or DPO-CC showed UL-94 V-0 level. • The PHRR and THR of EP containing 5 wt% DPO-CC decreased by 42.0% and 39.7%, respectively. • EP containing DOPO-CC or DPO-CC exhibited better mechanical properties than pure EP. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cardanol was applied to capture excess carbon dioxide from industry. • The bio-based NIPUs were synthesized from cardanol and carbon dioxide. • The comprehensive improvement effect of +5 valence of P was better than that of +3. • The modification of the intrinsic structure achieved eminent adhesion performance. Under the background of fossil fuel depletion and global warming, the large amount of carbon dioxide (CO 2) produced by industrial production was a renewable, clean and natural C1 feedstock that was becoming an ideal feedstock to produce value-added chemicals. The synthesis of non-isocyanate polyurethanes (NIPU) from cyclic carbonates as intermediate products was a typical way to realize the efficient recycling of CO 2. To improve the low carbonization, flammability and poor mechanics of NIPU and expand its application scenarios, the NIPU was synthesized from biological cardanol and CO 2 by a relatively green synthesis route, and modified by flame retardants containing different valence phosphorus. Compared with ECH-CarCO 2 -HMDA, the char residue of PO-CarCO 2 -HMDA and PP-CarCO 2 -HMDA increased by 248.8 % and 172.7 % respectively under nitrogen atmosphere, and 345.7 % and 151.9 % respectively under air atmosphere. More importantly, the peaks of heat release rate of modified NIPUs were reduced by 30.0 % and 18.4 %, and their total heat release were decreased by 15.2 % and 10.4 %, respectively. After various characterization analysis, this was mainly due to the generation of heat-stable structure containing phosphorus and oxygen during the burning process. Simultaneously, the toughness of PO-CarCO 2 -HMDA and PP-CarCO 2 -HMDA increased by 261.0 % and 105.1 %. In addition, the synthetic NIPU as an adhesive in different materials was also explored, and the adhesion strength can reach 2.47 MPa. This study provided a new idea for preparing bio-based NIPU which was more widely used. [ABSTRACT FROM AUTHOR]