Preparation And Performance Of Anode Materials For Lithium/Sodium Ion Batteries

With the rapid development of science and technology,continuous consumption of non-renewable fossible fules,the world is suffering from a serious energy challenge,which leads to a greater focus on exploring low-cost,high-benefit and pollution-free energy,such as solar energy,wind power,nuclear energy,etc.And scientists are working on a variety of energy storage devices to convert and store these renewable energy sources.In many energy storage devices,lithium ion batteries are ideal storage devices due to high energy density,long cycle life and small pollution.With the rapid development of science and techongy,lithium ion battery will be widely used in hybrid electric vehicles,biomedicine and so on.However,exentisve application of lithium ion battery has led to a sharp rise in the price of lithium.In addition,the lack of lithium resources makes people grow increasingly anxious.Sodium-ion battery as another kind of energy storage devices has attracted great attention of researches for the abundant and low cost sodium resources.Whether it is a lithium ion battery or sodium ion battery,the capacity,stability and rate performance of rechargeable batteries are important indicators of battery performance.Electrode is the core of battery,consists of active material,conductive carbon black and binder.In recent years,the research and development of negative electrode materials of lithium-ion batteries and sodium-ion batteries are very active in the world and have made a great progress.The Integrality of crystal structure,and the irreversible change of the structure in charge and discharge process is the key to obtain high specific capacity and long cycle life of the battery.In this paper,we synthetized different nanomaterials by electrospining,atomic layer deposition and facile hydrothermal,and studied the performance of lithium ion battery and sodium ion battery.The main research contents are as follows:?1?Uniform Ge@G@TiO₂ core-shell structure nanowire arrays were successfully fabricated by electrospining and atomic layer deposition,applied in lithium-ion battery?LIBs?.The testing results show that coating an appropriate thickness of TiO₂ shell can greatly improve the rate performance and cycle stability.?2?We obtained nitrogen doped carbon nanorods by a facile hydrothermal,and studied the effects on the electrochemical of different temperature.It is found that the nitrogen content does not change greatly at different temperature,but the electrochemical of the material is highly related to the temperature.The material treated at 700oC exhibits the best electrochemical performance.A high capacity of 587mAh g^-1,can be obtained after 500 cycles.?3?Made Ge@G@TiO₂ nanowire arrays as anode for sodium-ion battery?SIB?,and studied its electrochemical performance.The initial coulombic efficiency is a little low at a current density of 100 mA g^-1,but keep a high capacity of 190 mAh g^-1,after250 cycles,as well as a high coulombic efficiency.Compared with Ge and Ge@G nanowires,TiO₂ uniformly coated on the surface of Ge@G nanowires displayed not only a very high capacity,but also a sustainable cycle performance.