Research On Design,Controllable Preparation And Lithium Storage Properties Of Cobalt-and Tin-based Composite Structures

As a practical energy storage technology,lithium ion battery occupies a dominant position in the market of portable electronic products today.When graphite is used as electrode anode material,the theoretical capacity of lithium ion battery is 372 mAh g-1.However,with the increasing demand for battery capacity,cycle life and so on,the traditional lithium ion battery materials can not fully meet the current needs,and can not directly apply the carbon-based negative electrode to large electrical equipment that needs high capacity.Therefore,it is urgent to develop a new generation of battery materials.In view of the above problems of lithium ion batteries,the paper designs a one-dimensional cobalt phosphide nanorods and graphene-loaded tin dioxide nanorods,respectively.The main contents are as follows:(1)A self-template and self-catalytic strategy for the fabrication of the CoP@C core-shell nanoparticles encapsulated in one-dimensional porous carbon framework intertwined with N-doped carbon nanotubes(denoted as CoP@CcPCF/NCNTs)via a self-fabricated single precursor and subsequent thermal treatment in an inert atmosphere was presented.In this work,the CoP@carbon core-shell structure was combined with the NCNTs via the transformation of g-C3N4 catalyzed by Co nanoparticles,achieving synchronous growth of NCNTs on the surface of the material.When used as anode materials for lithium-ion batteries,the reversible specific capacity can be maintained at 712 mAh g-1 at a current density of 0.5 A g-1 after 700 cycles.When assembled into full cells with LiFeP04 as cathode,it can cycle 100 cycles at a current density of 0.2 A g-1 with a specific capacity of 113 mAh g-1.(2)The tin dioxide composite graphene cross-linked structure with a large specific surface area was obtained by one-step annealing treatment and simple solvothermal reaction after simple recombination and assembly of one-dimensional nanorod precursors and two-dimensional graphene oxide.The unique multi-scale,multidimensional,and hierarchical ordered structural design enables each component to contribute their respective strengths at the same time.Compared with the simple tin dioxide anode materials,it shows better performance in reversibility,cycling stability and rate capability.When the current density is 0.5 A g-1,the capacity can be maintained at 587.7 mAh g-1 after 300 cycles.