Design Of Alloy Material For Na-storage And All-solid-state Electrolyte

In 1990,lithium ion battery?LIBs?energy storage devices began to be applied in the field of electronic equipments.After more than 20 years improvements of process and technology,lithium secondary batteries have successfully occupied the market of small electric devices?such as mobile phone,computer,and digital camera?.However,the traditional LIBs are actually found to be plagued by low energy density and safety factor,which is unable to meet the requirements in large storage devices such as electric vehicles and national grid.Thus,it is important to meet market demand by improving the energy density and safety performance of lithium ion battery.The all-solid-state lithium batteries are considered to be an optimal alternative choice to traditional LIBs in terms of full realization of high performances and safety battery in the future.Considering the fact that lithium suffers low abundance in the earth,sodium ion batteries?SIBs?are considered to be potential alternative to LIBs owing to the higher abundance and similar working mechanism in comparison with Li.Electrode materials of the SIBs are critical to their applications in practical batteries,and exploring anode material with high capacity is an effective tactics for realization of high peformance SIBs.In this thesis,the main research contents are as following:1.We developed an in-situ hydrolytic strategy to synthesize SiO₂ nanoparticles,which were incorporated in poly?ethylene oxide?based polymer in term of lithium salt with large anions?LiBOB?.The electrochemical window,ion transference number,and ion conductivity of all-solid-state composite polymer electrolyte?ASSCPE?have been measured.The synthesized ASSCPE showed an exciting ion conductivity of 1.9 mS/cm at 80?.Moreover,the Li/LiFePO₄ battery assembled by the ASSCPE exhibited a superior reversible capacity of156.3 mAh/g under 0.05 C at 60?.It is suggested that the prepared ASSCPE has the potential for practical application as high-temperature batteries.2.We found a facile way to prepare a Sb@graphene?LS-Sb@G?micro/nanocomposite by typical solvothermal method.In this composite,the Sb nanosheets were uniformly coated on the graphene framework and further embedded into the interlayers,which results in the formation of dense layer-by-layer micro/nanostructure.When it was employed as anode materials for SIBs,the as-prepared LS-Sb@G exhibited superior Na-storage properties in terms of high Na-storage capacity,such as high reversible capacity of 495.2 mAh/g under 125mA/g after 100 cycles and good rate properties up to 6 A/g.Furthermore,application of the LS-Sb@G electrode was demonstrated by fabricated sodium ion full cells.The battery showed an impressive discharge capacity of 116.5 mAh/g at current density of 0.1 C.In addition,we investigated the Na-storage properties of Sb-based composite at-20? for the first time.