Preparation Of Bimetallic Oxides@Reduced Graphene Oxide Nanocomposites And Their Corresponding Lithium Ion Storage Properties

Lately,the worsening crises containing environmental contamination and depletionofenergyresourceshavecompelledusshiftingfocus on sustainable energy resources.The energy storage and conversion technology that in high-efficiency enable it possible for the effective utilization towards regenerative energy.What's particularly significant is the evolution of portable products with addition of plenty merits for lithium-ion batteries?LIBs?themselves,the LIBs are highly favoured.The carbon anode that commercialized exerted inferior energy density and confined specific capacity(372 mAh g^-1),which astricted its application severely.The capacity of carbon that N-doped and graphene was not exceeding 600 m Ah g^-1,but due to the forceful appeal among graphene layers,graphene that in solid lost the higher specific area that monodispersed graphene owes owing to aggregation.Hence,preparation of the three-dimensional rGO?3D rGO?appears needful.As researched,bimetallic oxide?BMO?anodes which drawn swingeing attention for the viable oxidation state,superior electroconductivity and synergistic action between them and whose properties were more outstanding than the single one.They demonstrated merits including lower ion-diffusion resistance and the facile electrolyte penetration,nevertheless,the materials pulverization and structures collapse among cycling induced the weak stability.Based above all,envisioning that integrating BMOs with 3D rGO could settle the puzzle practically.The3D rGO acts as a supporting and conductive skelecton loading BMOs,which could boost conductivityofoxidesthatanchoredon,bufferpressureeffectamong lithiation/delithiation and sequentially promote the lithium storage.The graphene-based composites which were registered were acquired merely via a traditionally“one-pot”process,during which the graphene mixed simply with inorganic substances.While the sandwich-structured graphene based nanocomposites synthesized in this text settled the comprehensive questions above.The primary researches are below:1.A 3D columnar rGO was obtained through GO sheets via a hydrothermal synthesis,and then a soaking and the succedent secondary growth was exerted to synthesize NiMn₂O₄@rGO nanocomposite,during which the NiMn₂O₄ nanosheets anchored equally and compactly on both sides of rGO.The NiMn₂O₄ loading amount on rGO was controlled by adjusting solution concentration for Ni Mn₂O₄ precursors.The composite electrode exhibited a capacity of 867 mAh g^-11 cycled for 500 times at 2 A g^-11 in NiMn₂O₄@rGO//Li half-cell and 1046 m Ah g^-11 at 0.05 A g^-11 for 60 cycles in NiMn₂O₄@rGO//LiCoO₂ full-cell.It was verified that existence of rGO and synergistic effect between them was conducive to lithium storage.2.The above presented rGO was regarded as a substrate,taken CoCl₂?6H₂O,NiSO₄?6H₂O,C₆H₁₂N₄ and VC for ingredient to configurate the pellucid solution.Via adsorption/diffusion routes,a hydrothermal in-situ growth and the subsequent annealing process,the NiCo₂O₄ nanoparticles adhering effectively on the rGO.The composite electrode delivered a capacity of 1566 mAh g^-1?1 A g^-11 for 700 times?in NiCo₂O₄@rGO//Li half-cell and 886 mAh g^-1?0.1 A g^-11 for 100 times?in NiCo₂O₄@rGO//LiCoO₂ full-cell.It could be generalized that rGO which serves as the conductive scalfold of Ni Co₂O₄ possesses ample disorder/defects,facilitating transfer of lithium-ions.3.To probe the universality of the above-mentioned technique that manufacturing the 3D rGO-based composites and probe electrochemical lithium-storage of Co-based BMO@rGO,this chapter described succinct and controllable electrostatic attraction of Zn²⁺and Co³⁺,and induce growth of ZnCo₂O₄ precursor nanobelts.With the step solvothermal and the eventual calcination,ZnCo₂O₄ nanoparticles distributed uniformly on rGO.The synthesized material presented a capacity of 1113 mAh g^-11 at 1 A g^-11 for 500cycles and 1589 mAh g^-11 at 0.1 A g^-11 for 140 cycles in ZnCo₂O₄@rGO//Li half-cell and ZnCo₂O₄@rGO//Li CoO₂ full-cell,respectively.It was confirmed that the forceful interaction between ZnCo₂O₄ and rGO was the essential factor that showed the preferable property.