| The silicon fertilizer application in rice production not only have the function of resisting lodging and resisting biological stress,but also could increase the rice and biological yield.Our country plays a pivotal role in the producing of rice,and huge amounts of rice by-products will be concomitantly produced.Therefore,exploring high added value utilization strategy for rice by-products is desirable,which could improve the rice cultivation environment and realize the sustainable development of field cultivation.The application of silicon fertilizer possesses potential effect on improving the biomass accumulation and the absorption content of silicon,nitrogen and phosphorus in rice,and the rice biomass with abundant silicon,nitrogen and phosphorus hold a promising application in alkali metal ion battery.Therefore,this thesis systematically studied the effects on the agronomic traits of rice with different seasons and cultivars at maturity stage after silicon fertilizer application,and systematically analyzed the absorption and distribution characteristics of silicon,nitrogen and phosphorus elements in different position of obtained by-products.The microstructure and chemical characteristics for different position of rice with different seasons and cultivars were analyzed via transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,Raman spectroscopy and X-ray diffraction（XRD）.The high efficiency energy utilization of rice by-products in alkali metal ion battery was studied based on characteristics of different rice by-products after applying silicon fertilizer.The main research results are as follows:The effects on agronomic traits and the content of silicon,nitrogen and phosphorus for different season of rice varieties after silicon fertilizer application were investigated via field experiments.The results showed that the yield and dry matter accumulation amounts for early and late season rice varieties exhibit an increasing trend after silicon fertilizer treatment,which the yield increased from 2.76%to 22.27%,and the dry matter accumulation increased from-6.35%to 29.11%.The silicon fertilizer treatment had obvious effect on the increasing of yield for conventional japonica rice（22.27%）and conventional indica rice（18.70%）in early season,and with similar increasing effect on hybrid japonica（10.92）and indica rice（18.41）in late season.Silicon fertilizer treatment could significantly increase the silicon content in each part of early season conventional japonica rice by-products,and the silicon content of rice husk was obviously higher than that of stem,leaf and branch.The nitrogen and phosphorus content of conventional japonica rice after silicon fertilizer application was higher than that of other rice varieties.In addition,the results showed that the nitrogen content in rice leaves was significantly higher than that of other parts,and the nitrogen and phosphorus content of late season conventional japonica rice leaves were significantly higher than that of other rice varieties after silicon fertilizer treatment.The silicon content of early season conventional japonica rice husk after silicon fertilizer treatment could reach 16.54%,which is 3.37 percent points higher than the husk before silicon fertilizer treatment.The preparation method of silicon-based composite electrode material from rice husk was innovated,achieving the goal of full using the silicon constitution and organic components of rice husk including cellulose,hemicellulose and lignin.The results of transmission electron microscopy,X-ray diffraction,Raman spectrometer and X-ray photoelectron spectroscopy showed that the rice husk was successfully converted into Si/C composite electrode materials for lithium-ion batteries.The silicon-based composite electrode exhibits an excellent rate performance and cycling stability with the capacity of 420.7 mAh g-1 at the rate of 3 C and retention ratio of 90%after 150 cycles at 0.5 C.Furthermore,the charge capacity of rice husk derived composite electrode is 136.1 mAh g-1than that of commercial graphite anode.The utilization efficiency of early season conventional japonica rice husk without and with silicon fertilizer application was compared,and the result shows that the composite electrode derived from rice husk after silicon fertilizer application exhibits the average capacity of 476.4 mAh g-1,which is 60.1 mAh g-1higher than that of rice husk and the charge capacity improved 14.5%,compared to without silicon fertilizer application.The result of scanning electron microscopy,transmission electron microscopy,X-ray diffractometry and Raman spectroscopy shows that the surface defects of biomass carbon materials could be enhanced by silicon fertilizer treatment,which is beneficial to Na+ion insertion and adsorption.The biomass carbon materials derived from different parts of rice by-products were applied in sodium ion batteries,and the result shows that the carbon materials derived from rice stem and rice branch could exhibit the capacity of 150 mAh g-1 and 135 mAh g-1,respectively,which were lower than that of rice leaf part.The biomass carbon materials derived from leaf part of rice by treatment with silicon fertilizer could exhibit an average capacity of 252.2 mAh g-1,which is 52.9 mAh g-1 higher than that of rice leaf without silicon fertilizer treatment and the capacity improve 26.5%.The theoretical calculation results show that the biomass carbon materials derived from rice leaf exhibit excellent sodium ion storage performance,which were attributed to the higher nitrogen and phosphorus content of leaf,providing sufficient active sites and binding center for sodium ions storage.In conclusion,the silicon content of early season conventional japonica rice husk and nitrogen and phosphorus content of late season conventional japonica rice leaf were significantly increased via silicon fertilizer application.In comparison with rice biomass without the application of silicon fertilizer,the rice biomass derived materials with the application of silicon fertilizer could significantly improve the capacity of anode materials in alkali metal ion battery. |
