Preparation Of Sn-based Materials And Application As Anode Material Of Lithium-Ion Batteries

Tin-based materials have attracted considerable attention and intense research because of the feature in terms of the high theoretical capacity.However,drastic volume expansion usually accompanies the lithiation/delithiation processe induces a large internal stress,leading to the disintegration of the electrode material and formation of an unstable solid-electrolyte interphase(SEI),which eventually results in a rapid degradation in capacity.To overcome above issues,researchs show that design and develop nanostructured materials,hollow structure and integrate the electrode material with nanocarbon can effective mitigate the volume expansion and to prevent the pulverization during the charge/discharge processes.It is the promising tactic to meet the requirement of the high energy density Li-ion power batteries.In this paper,tin-based materials are the main research direction.We demonstrate a simple and scalable strategy to construct three materials which are tin nanoparticles encapsulated nitrogen-doped hollow carbon spheres,3D graphene network encapsulating SrnO2 hollow spheres and 3D macroporous nitrogen-doped carbon nanosheet networks anchored with SnS nanoparticle.The present tin-based materials exhibit an outstanding electrochemical performance,which is attributed to the unique robust architecture design.The following main innovation results were obtained:(1)Compared to the Sn/C which obtained from the tin oleate in the high temperature heat treatment,performance of Sn@N-HPC are obviously improved in terms of high reversible specific capacity,cycling stability,and good rate capability.The as-developed Sn@N-HPC shows a high reversible capacity of 912 mAh g-1 after 200 cycles at a current density of 0.1 A g-1and Sn/C only has 84 mA h g-1 after 100 cycles,demonstrating that nitrogen-doped hollow carbon spheres because of the internal empty space can mitigate the volume expansion during the charge/discharge processes and facilitate fast electron/ion transportation throughout the entire electrode,so obtained good cycling stability,and good rate capability.(2)The as-designed H-SnO2@rGO has a unique three-dimensional(3D)nanostructure with favorable features for lithium ions storage,not only provides robust protection against the aggregation and volume changes of SnO2 nanospheres,but also ensures highly favorable transport kinetics for both electrons and lithium ions.A high reversible capacity of 1107 mAh g-1 can be retained after 100 cycles at a current density of 0.1 A g-1 and maintained 552 mAh g-1 over 500 cycles at a current density up to 1 A g-1.The as-designed H-SnO2@rGO exhibits an outstanding electrochemical performance as anode material of lithium-ion batteries.(3)The nitrogen-doped carbon nanosheets in 3D SnS@N-CNNs not only restrict SnS growth but also provide high electronic/ion conductivity.In addition,3D network frame structure provides necessary void space to degrade the volume expansion for SnS during charge/discharge process.The as-designed 3D SnS@N-CNNs exhibits an outstanding electrochemical performance as anode material of lithium-ion batteries.A high reversible capacity of 938 mAh g-1 can be retained after 50 cycles at a current density of 0.1 A g-1 and maintained 470 mAh g-1 over 700 cycles at a current density up to 1Ag-1.