First-principles Calculations And Mesoscale Simulations Of The New Energy Battery Materials

Under the requirements for the sustainable development of energy and environmental protection, new energy battery technology of transforming various clean energy sources(such as hydrogen fuel, solar energy, etc.) into electrical energy and the development of some new materials for battery electrodes both plays a significant role in promoting the "greening" process of the energy-resource structure further. In recent years,some new energy conversion technologies including hydrogen fuel cells, lithium ion batteries and organic solar cells have been followed and investigated extensively. Some of the new energy battery technology has even been produced and applied in large-scale, there are still some problems to be solved in the further development and promotion of such clean energy battery. For instance, once the CO impurities and other harmful gases in the hydrogen gas get into the fuel cell, it will cause the "poisoning" of the Pt catalyst, resulting in irreversible damage to the cathode catalyst. Therefore, the exploitation of the efficient CO oxidation catalyst in extending the lifetime of the hydrogen fuel is very considerable. Besides, lithium-ion battery has been widely used in the portable electronic devices, but the charging process of the battery is still slow and the related power is relatively low. So, it is nessesary to design new electrode material with stable structure, low energy barrier for Li migration and high storage capacity so as to improve the related performance of lithium-ion batteries. Moreover, polymer solar cells have been focused intensively based on the property of light weight, soft, non-pollution etc. However, the research about the relationship among the preparation parameters, morphology and device efficiency of the polymer solar cells is still not sufficient, which severely limits the improvement of the corrsponding efficiency. Thus it is vitally significant to illustrate the dynamic phase separation process and predict performance indicator of the polymer solar cells with theoretical calculation method.We discussed the reaction mechanism of carbon monoxide catalytic oxidation on the surface of molybdenum disulfide group-platinum single atomic catalysts(SACs) with the first-principles calculations method. Based on such MoS2 supported Pt catalyst, we can not only significantly improve the utilization of the metal atoms but also effectively reduce the CO oxidation reaction energy barrier. Therefore, it turned out to be an efficient solid catalyst and shown good application prospects in the purification of the hydrogen source of the hydrogen fuel cells. In addition, the underly mechanism of the pre-lithiated two-dimensional layer sulfide(LixMS2, M = Mo, W, V) as the Li-ion batteries(LIBs) anode materials was investigated as well. Based on the theoretical research, we found that the adsorption of Li on the surface of the two-dimensional LixMS2 is more stable, the related diffusion energy barrier is quite low and the storage capacity is relatively high. Thus, the development of such novel anode material is helpful for the promotion of the commercial application of such green energy power. Furthermore, we investigated the desolvation processes of two typical polymer/fullerene derivative solar cells(PSCs) through dissipative particle dynamics(DPD) simulation method, and systematically analyzed the internal mechanism of the effect of processing parameters on the morphology of the polymer system. Then we successfully evaluated the performance indicators of the related PSCs devices through the combination of graph theory and definitions of the morphology descriptors. We finally gained a suitable set of preparation parameters which is beneficial to the formation of the bi-continuous network morphology and help to improve the efficiency of photovoltaic cells effectively.Based on the atomic scale first principles calculations and mesosale theoretical simulations above, we have successfully indicated the main corresponding internal mechanism of the efficient single atomic catalysts, lithium ion battery anode materials, polymer solar cells, and systematically summarized the critical factors affecting the corresponding device performance respectively, proposing effective approaches to elevate the efficiency of heterogeneous catalyst, lithium ion battery and polymer solar cells, thus providing a reliable theoretical basis for its practical application.