State Key Laboratory of Fire Science

Structure of hexagonal boron nitride (h-BN) is similar to that of graphite before functionalization and exfoliation.

Functionalized reduced graphene oxide (FRGO) wrapped with a phosphorus and nitrogen-containing flame retardant (FR) was successfully prepared <italic>via</italic> a simple one-pot method and well characterized.

A C80 calorimeter was used to study the thermal behaviors of and in electrolyte. C80 results show that alone shows one exothermic peak, which is attributed to the solid electrolyte interphase (SEI) decomposition. Four exothermic peaks were detected in electrolyte samples. These four peaks are attributed to SEI decomposition, Li-electrolyte reaction as well as new SEI film formation, new SEI film decomposition, and Li with PVDF/other products reactions. The apparent activation energy of and -electrolyte at different states of charge was calculated, and it was found that with intercalated lithium increasing, the activation energy shows a decreasing trend.

Schematic of the lithium-ion battery and description of the P2D electrochemical model.

Polymer/graphene-analogous nanosheet composites have great potential for improving their physical and mechanical properties during the past few years.

A lithium-ion battery (LIB) may experience overcharge or over-discharge when it is used in a battery pack because of capacity variation of different batteries in the pack and the difficulty of maintaining identical state of charge (SOC) of every single battery. A series of experiments were established to investigate the thermal and fire characteristics of a commercial LIB under overcharge/over-discharge failure conditions. According to the results, it is clear that the batteries experienced a clear temperature rise in the overcharge/over-discharge process. The temperature rise worsened and required less time when the battery was overcharged/over-discharged to failure with the increasing charge/discharge rate. Besides, the closer the position to the opening of the battery, the higher the surface temperature. It was demonstrated that LIBs can fail when overcharged/over-discharged to a critical degree regardless of the charge/discharge rate. Under different rates, the final capacities were around a critical value. Finally, there existed an explosion phenomenon in the external heating test of battery failure after overcharge, whereas the fire behaviors of the over-discharged battery were much more moderate.

Owing to the outstanding mechanical strength and modulus, high <italic>T</italic>_g, anti-flammability and anti-bacterial property, this fully bio-based epoxy thermoset is a promising substitute for DGEBA-based thermoset in high performance fire safe applications.

. Accordingly, these results have implications in the fire suppression design for lithium-ion batteries.

The effect of doping different heteroatoms including nitrogen, boron and phosphorus on the thermal oxidation of RGO is investigated.

A freeze-drying method is firstly used to prepare a flexible and robust HAPs/PVA separator for stable, safe and sustainable Li metal batteries.

In the current work, a series of experiments were carried out under low and normal temperature conditions (0 and 20 °C) to research the influence of low temperature on the performance of lithium-ion batteries (LIBs). Besides this, a commercial insulation material (IM) was employed to research its effect on preventing damage in a battery exposed to low temperature. Based on the experimental results, it was found that the battery exhibited a higher temperature increase at low ambient temperature due to the larger internal resistance of the battery at low temperature, which resulted in greater heat generation. It was also observed that the low temperature caused the uniformity of the battery to deteriorate as a result of temperature and voltage differences, and the uniformity became poorer with increasing cycle rate. Moreover, the capacity decay rate of the battery was demonstrated to be greatly accelerated by the low temperature. According to the morphological changes of the battery components, the structure of the electrode materials and separator was damaged under low temperature conditions. Finally, the results show that the IM had a significant effect on warming the battery up; therefore, a much better discharge performance and slower decay rate of the battery were achieved. Furthermore, the performance of the IM was found to be related to its thickness.

Safety issue of lithium-ion batteries (LIBs) is always a concern. We have studied the inhabitation on thermal runaway (TR) and propagation of 18,650 LIBs in an enclosed space systematically. LIBs at 70% state of charge are chosen for testing. Four fire extinguishing agents are applied on LIB arrays for 20 s, and the inhibiting effects are different. The cooling efficiency varies with the surface temperatures of LIBs. Water spray has the highest cooling efficiency and inhibits the TR propagation among LIB arrays successfully. Three LIBs undergo TR for the releasing of ABC ultrafine dry powder. BC ultrafine dry powder and Novec 1230 are failed to inhibit the TR propagation. Nevertheless, Novec 1230 shows the best on inhibiting fire occurring and the generation of toxic gas. Generally, this study provides valuable information for the choice of fire extinguishing agents.

interaction/extraction process and thus giving it superb electrochemical property. This work may represent an important step forward in the fabrication of MOF-derived hierarchical hybrids combined with a hollow structure and TMCs to help such TMCs achieve their potential in energy storage systems.

To improve the safety of lithium-ion batteries, 4-isopropyl phenyl diphenyl phosphate (IPPP) was used as a flame-retardant additive in a electrolyte solution. The flammability and thermal stability of IPPP-containing electrolytes were investigated by means of burning test and microcalorimetry. It was found that the addition of IPPP can reduce the flammability, and delay the onset temperature of a major exothermal reaction of the electrolyte. Furthermore, the electrochemical performances of cells become slightly worse after using IPPP additive in the electrolyte. This alleviated trade-off between electrolyte flammability, thermal stability, and cell performance provides a possibility to formulate a nonflammable electrolyte containing 5–15% of IPPP and improve the electrolyte thermal stability with a minimal sacrifice in performance.

Thermal stabilities of different lithium salts and the roles of the salts on the thermal behaviors of their based electrolytes and electrolyte– coexisting systems were analyzed by a C80 microcalorimeter in this paper. For the salts lithium hexafluorophosphate , lithium tetrafluoroborate , lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), and lithium bis(oxalate)borate (LiBOB), there is no exothermic behavior was detected. The mixture systems without lithium salts present relatively stable thermal behavior. The thermal stability of solvents is greatly reduced after the addition of lithium salt, especially for the -based electrolyte. The special structure and composition of LiBOB enable the LiBOB-based electrolyte to show excellent thermal stability. The thermal stability of the electrolyte– coexisting system is mainly determined by the electrolyte not by and the LiBOB-based coexisting system shows better thermal characteristics.

Significant improvements in thermal and flame retardant properties of polymeric materials at low loadings hold tremendous promise for fire safety materials.

Novel nanoflower-like N-doped C/CoS2 spheres assembled from 2D wrinkled CoS2 nanosheets were synthesized through a facile one-pot solvothermal method followed by sulfurization. Ascribed to the optimized 3D nanostructure and rational surface engineering, the unique hierarchical structure of the nanoflower-like C/CoS2 composites showed an excellent sodium ion storage capacity accompanied by high specific capacity, superior rate performance and long-term cycling stability. Specifically, the conductive interconnected wrinkled nanosheets create a number of mesoporous structures and thus can greatly release the mechanical stress caused by Na+ insertion/extraction. Besides, it was observed from the experiments that many extra defect vacancies and Na+ storage sites are introduced by the nitrogen doping process. It was also observed that the crosslinked 2D nanosheets can effectively reduce the diffusion lengths of sodium ions and electrons, resulting in an outstanding rate performance (>700 mA h g-1 at 1 A g-1 and 458 mA h g-1 at even 10 A g-1) and extraordinary cycling stability (698 mA h g-1 at 1 A g-1 after 500 cycles). The results provide a facile approach to fabricate promising anode materials for high-performance sodium-ion batteries (SIBs).

Fire accidents are influenced by many complex factors, and it has the characteristic of both randomicity and fluctuation, so a new forecasting model (Grey-Markov model) was established in order to forecast fire accidents effectively in this paper, which has the merits of both GM (1, 1) forecast model and Markov chain forecast model, it can reduce random fluctuation of accident data affecting forecasting precision and develop the application scope of Grey forecast. Finally, an example was analyzed, the results show that Grey-Markov model proposed in this paper has a higher forecast precision and excellent applicability.

A halogen-free phosphorus-containing monomer (TAOPO) was successfully synthesized and used as a co-curing agent to prepare intrinsic flame-retardant unsaturated polyester resin (FR-UPR) by radical bulk polymerization with different TAOPO content.

Poly(bis(phenoxy)phosphazene) combining with expandable graphite exhibit gaseous phase and condensed phase flame mechanism in PLA matrix.