Preparation And Energy Storage Performance Of Metal Silicate Nanomaterials

As a new type of battery,lithium-ion batteries are considered to be the main energy storage devices in electric vehicles and military and civilian small appliances.With the increasing demand for energy,the exploration and development of high-performance electrode materials for lithium-ion batteries is becoming more and more important,but the commercial anode material is mainly graphite,and its specific capacity is 372 mAh/g.Therefore,it is imperative to choose a negative electrode material with a high specific capacity.Metal silicates have received a lot of attention due to their low cost,easy synthesis,environmental friendliness,etc.,and they also have high theoretical capacity and good cycle stability.In this paper,manganese silicate and its composites were prepared by simple synthesis method as anode materials for lithium ion batteries and their electrochemical properties were studied,the specific research content is as follows:?1?Graphene-coated amorphous manganese silicate particulate material was prepared by simple hydrothermal method as the negative electrode of lithium ion battery.The composite material?MnSiO₃/RGO?has a loose amorphous structure,can accommodate a large number of electrochemically active substances,effectively alleviates volume expansion and provides many fast transmission channels for lithium ions.Secondly,the use of graphene to encapsulate the manganese silicate particles also alleviates the volume expansion of the manganese silicate during the lithiation/delithiation process.The test results show that the prepared negative electrode material exhibits excellent cycle and rate performance,and after 200 cycles at a current density of 0.1 A/g,it shows a large specific capacity of up to 836.4 mAh/g.The negative electrode material has a much larger capacity than the commercial graphite negative electrode material,and the cycle stability is very good.?2?A sandwich sandwich structure manganese silicate graphene manganese silicate?MnSiO₃@RGO@MnSiO₃?composite was prepared by hydrothermal method as a negative electrode of a lithium ion battery.The sandwich sandwich structure in this material has a large specific surface area to promote lithium ion storage capacity,and it has a high porosity and can be used to enhance charge transport,thereby increasing the transfer rate.Graphene enhances the electrical conductivity of the material and improves electrochemical stability.The test results show considerable capacity and superior rate performance.The anode material showed a high specific capacity of 586.8 mAh/g after 200 cycles at a current density of 0.1A/g.Through the rate performance test,when the current density returned to 0.1 A/g after 70cycles,the anode still provided a large reversible capacity of 544.6 mAh/g with a capacity retention of 87.8%,indicating that the anode material has better reversibility.?3?The carbon nanotube manganese silicate composite?CNT/MnSiO₃?was prepared by hydrothermal method as the negative electrode of lithium ion battery.The carbon nanotubes are uniformly coated with a layer of silica by hydrolysis of tetraethyl orthosilicate,and then SiO₃^2-is formed under alkaline conditions in a hydrothermal process,and combined with Mn²⁺to form manganese silicate.The tubular carbon nanotubes can accelerate the diffusion of lithium ions,improve the conductivity of the material,and alleviate volume expansion during repeated cycles.Three kinds of different silica coatings were prepared for comparison.The results showed that 0.6ml of tetraethyl orthosilicate hydrolyzed silica prepared the best electrochemical properties.After 70 cycles at a current density of 0.1 A/g,it showed a high specific capacity of 557.4 mAh/g,and shown good reversibility in the rate test as well as higher capacity at high current densities and its stability was very good.