In-depth investigation of the exothermic reactions between lithiated graphite and electrolyte in lithium-ion battery

Thermal runaway is a critical issue for the large application of lithium-ion batteries.Exothermic reactions between lithiated graphite and electrolyte play a crucial role in the thermal runaway of lithium-ion batteries.However,the role of each component in the electrolyte during the exothermic reactions with lithiated graphite has not been fully understood.In this paper,the exothermic reactions between lithiated graphite and electrolyte of lithium-ion battery are investigated through differential scanning calorimetry(DSC) and evolved gas analysis.The lithiated graphite in the presence of electrolyte exhibit three exothermic peaks during DSC test.The reactions between lithiated graphite and LiPF_(6) and ethylene carbonate are found to be responsible for the first two exothermic peaks,while the third exothermic peak is attributed to the reaction between lithiated graphite and binder.In contrast,diethylene carbonate and ethyl methyl carbonate contribute little to the total heat generation of graphite-electrolyte reactions.The reaction mechanism between lithiated graphite and electrolyte,including the major reaction equations and gas products,are summarized.Finally,DSC tests on samples with various amounts of electrolyte are performed to clarify the quantitative relationship between lithiated graphite and electrolyte during the exothermic reactions.2.5 mg of lithiated graphite (Li_(0.8627)C_(6)) can fully react with around 7.2 mg electrolyte,releasing a heat generation of 2491 J g^(-1).The results presented in this study can provide useful guidance for the safety improvement of lithium-ion batteries.

The Dynamic Flexibility of Batch Exothermic Reaction System： Take into Account the Effect of the Initial Operational Temperature

It is shown in this article that by changing the initial operation condition of the batch processes, the dynamic performance of the system can be varied largely, especially for the initial operational temperature of the exothermic reaction. The initial operation condition is often ignored in the designing batch processes for flexibility against disturbances or parameter variations. When the initial condition is not rigid as in the case of a batch reactor, where the initial reaction temperature is quite arbitrary, optimization can also be applied to determine the ＂best＂ initial condition to use. Problems for dynamic flexibility analysis of exothermic reaction including initial temperature and process operation can be formulated as dynamic optimization problems. Formulations are derived when the initial conditions are considered or not. When the initial conditions are considered, the initial condition can be transferred into control variables in the first optimal step. The solution of the dynamic optimization is on the basis of Rugge-Kutta integration algorithm and decomposition search algorithm. This method, as illustrated and tested with two highly nonlinear process problems, enables the determination of the optimal level. The dynamic performance is improved by the proposed method in the two exothermic reaction examples.

Heat Propagation of Eyring-Prandtl Double Reaction and Pressure Driven Hydromagnetic Viscous Heating Fluid in a Device

The effect toxic industrial discharge on the environment and ecosystem cannot be overlooked. This is owing to a partial combustion of hydrocarbon arising from industrial activities and human endeavours. As such, this investigation focuses on the pressure driven flow and heat propagation of combustible Prandtl-Eyring viscous heating fluid in a horizontal device. The combustion-reaction of the viscoplastic material is considered to be inspired by two-step exothermic reaction. With negligible reactant consumption, the flowing fluid is influenced by a chemical kinetic, activation energy and electromagnetic force. An invariant transformation of the partial derivative model to an ordinary derivative model is obtained through an applied dimensionless variable. The solutions to the unsteady thermal fluid flow model are obtained via a semi-implicit difference scheme, and the outputs of the solution are displayed in plots and tables. As revealed, an enhanced heat propagation is obtained that in turn encourages the combustion process of the system. Also, increasing material dilatant simulated fluid molecular bond and viscosity. Therefore, the outcomes of this study are treasured to the thermal and chemical engineering, and the environmental management.

An efficient light-to-heat conversion coupling photothermal effect and exothermic chemical reaction in Au NRs/V_(2)C MXene membranes for high-performance laser ignition

MXene,a new type of two-dimensional materials,have been demonstrated as one of the best photothermal materials owing to their strong light-matter interaction and high photothermal conversion efficiency in recent years.Herein,we report the intriguing light-to-heat conversion property of vanadium carbide(V_(2)C)MXene under irradiation of millisecond laser pulse.Unlike the typical photothermal materials,the V_(2)C MXene not only converts the incident laser energy to heat by the physical photothermal effect,but also triggers the exothermic oxidation of the V_(2)C MXene.The oxidation could be greatly promoted with addition of plasmonic Au nanorods(Au NRs)for light absorption enhancement.Owing to the unique light-to-heat conversion property,the Au NRs/V_(2)C MXene membrane could serve as high temperature pulse(HTP)generators that is proposed for numerous applications with high demand for immediacy.As a proof-of concept application,Au NRs/V_(2)C MXene membrane was applied for laser ignition of the high energy density materials,such as 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane(HNIW or CL-20).An improved ignition performance,in terms of lowered laser threshold,is achieved as compared to the state-of-the-art light-to-heat conversion materials.

Temperature fault-tolerant control system of CSTR with coil and jacket heat exchanger based on dual control and fault diagnosis

For the characteristics of the continuous stirred-tank reactor(CSTR) with coil and jacket cooling system,a CSTR temperature dual control solution based on the analysis of the CSTR exothermic reaction control characteristic was proposed for an organic material polymerization production.The control solution has passive fault-tolerant ability for the jacket cooling water cutting off fault and active fault-tolerant potential for the coil cooling water cutting off fault,and it has good control ability,high saving energy and reducing consumption performance.Fault detection and diagnosis and fault-tolerant control strategy are designed for the coil cooling fault to achieve the active fault-tolerant control function.The CSTR temperature dual control,process fault detection and diagnosis and active fault-tolerant control were full integrated into the CSTR temperature fault-tolerant control system,which achieve fault tolerance control of CSTR temperature for any severe malfunction of jacket cooling or coil cooling cutting off,and the security for CSTR exothermic reaction is improved.Finally,the effectiveness of this system was validated by semi-physical simulation experiment.

Modification of Glucose Molecules with Alkali Elements as a Method to Dissolve Cancer Cells

Cancer cells are irresponsive to the central control of the cell growth mechanisms. It is difficult to turn on the responsive mechanism of cancer cells because the cells are completely dissociated from the central command and on their own in terms of cell division and growth. Precisely, this is the reason why they are at risk to the health of humans and/or any biological entities. Instead of trying to reconnect the central command of the growth control mechanism to cancer cells that are already out of the range, we present a method for using the cancer cell’s own irresponsive and uncontrolled growth mechanism to their disadvantage and destroy the cancer cells. We found that this is achievable in an atomic/molecular level study of the glucose molecule, which is the primary food source used for growth and energy generation by all cells in the body, including cancer cells. Testimonials of the clinical trial of the supplement provide proof of dramatic recovery from the advanced stage of cancer in seven days.

Dissociation of liquid water on defective rutile TiO2 （110） surfaces using ab initio molecular dynamics simulations

In order to obtain a comprehensive understanding of both thermodynamics and kinetics of water dissociation on TiO2, the reactions between liquid water and perfect and defective rutile TiO2 （110） surfaces were investigated using ab initio molecular dynamics simulations. The results showed that the free-energy barrier （-4.4 kcal/mol） is too high for a spontaneous dissociation of water on the perfect rutile （110） surface at a low temperature. The most stable oxygen vacancy （VOl） on the rutile （110） surface cannot promote the dissociation of water, while other unstable oxygen vacancies can significantly enhance the water dissociation rate. This is opposite to the general understanding that Vol defects are active sites for water dissociation. Furthermore, we reveal that water dissociation is an exothermic reaction, which demonstrates that the dissociated state of the adsorbed water is thermodynamically favorable for both perfect and defective futile （110） surfaces. The dissociation adsorption of water can also increase the hydrophilicity of TiO2.