Hierarchical Porous Carbon-based Composite Materials As Anode For Lithium-ion Batteries

As a key application of new energy development,Lithium-ion batteries(LIBs)have been widely used in all aspects of our lives.Improving the electrochemical performance of Li-ion battery materials has been concerned and studied by many researchers.Carbon based anode materials have been favoriting in both research and commercial field because of its good chemical stability,high conductivity and inexpensiveness and easy-to-obtain.However,the theoretical capacity of commercial graphite is only 372 mAh·g-1,which cannot meet people’s needs at all.At present,carbon-based composite materials as high-performance anode materials are heralding the challenges of further research and development in terms of market competition and application prospects.In the previous work of our research group,we have developed a method for the synthesis of hierarchical porous carbon-based composite materials,which can be used in various catalytic chemical and electrochemical reactions.Based on this method,we developed a nickel-catalyzed in-situ growth of three-dimensional(3D)hierarchical porous carbon structure,which was combined with iron oxide to form a carbon-based composite material as the LIBs anode.This work has developed a simple,large-scale production of "solvent-free" synthesis method.can be applied to low-cost commercial use.Acetylacetone(Hacac)and nickel acetylacetonate(Ni(acac)2)are combined with iron oxide nanoparticles as the raw materials,and the base-catalyzed condensation forms the precursor,which was carbonized at high temperature to afford the required material.The hierarchical porous carbon anode material has a high charge capacity of 1125.2 mAh·g-1 at a current density of 0.1 A·g-1,and it also has high rate performance of 523.3 mAh·g-1 at a current density of 5 A·g-1.Meanwhile,in 1000 cycles under 0.5 A·g-1 current density indicates its long cycle life,as the capacity attenuation of each cycle is only 0.008%.From the measurement of the battery,we further confirmed the great prospect of hierarchical porous carbon material(T-HPC)as a negative electrode with long cycle life.Using acetylacetone and melamine,α-Fe2O3 was encapsulated by the in-situ generated carbon under calcination to obtain the iron oxide carbon composite material(CEFO)that was isolated by carbon nanotube structure.Under the current density of 0.5 A·g-1,the capacity of this material gradually increases by 832 mAh·g-1 after the first 50 cycles of activation,and it is very stable in the last 450 cycles without capacity decay.Subsequently,the current density was increased to 5 A·g-1 for cycle life test,and the performance was still very stable according to the measured data.The synthesis strategy proposed in this paper is expected to be applied to low-cost commercial applications.Our research has opened up a feasible method for the design of 3D porous carbon-based composite materials,which can be applied to lithium-ion battery anode materials with high storage capacity and structural stability.