| Compared with commercial graphite anode material,hard carbon anode material is a kind of carbon anode materials with relatively high capacity and good high rate performance.It not only has a wide range of sources,low price and high plasticity,but also has a long service life and excellent high-current discharge performance.Therefore,hard carbon material is a very promising anode material.However,it limits the wide application of hard carbon materials due to its disadvantages such as low efficiency and relatively low capacity for the first time.As a new type of two-dimensional material,black phosphorene has the advantages of high theoretical specific capacity,good carrier mobility and excellent large-current discharge capability,but it also limits its electrochemical performance due to it undergoes a large volume expansion during the cha rge-discharge reaction.In summary,the hard carbon material is subjected to hollow a nd porous modification to further improve the high-current discharge performance of the hard carbon anode material.Subsequently,the black phosphorene and the hollow porous carbon are compounded,and the volume expansion of the black phosphorene is relieved through the hollow porous structure,and the high capacity characteristic of the black phosphorene is fully exhibited,thereby improving the large-current discharge performance of the composite electrode.In this paper,the preparation of hollow porous carbon,compound modification and chemical bonding with black phosphorene and electrochemical performance of composite material were studied.The main conclusions are as follows:(1)The hollow porous structure makes the hard carbon ma terial have a larger specific surface area,more lithium storage active sites and more ion transmission channels,thus exerting the hard carbon material’s large-current discharge capability.The hollow porous carbon anode material still shows a reversible capacity exceeding170 m Ah/g after 1000 cycles at a current density of 1000 m A/g.(2)The solvothermal method combines black phosphorene with hollow porous carbon through chemical bonds(P-C bond,P-O-C bond),and its retained hollow porous structure which can effectively relieve the volume expansion of black phosphorene and improve the low coulomb efficiency and cycle performance of black phosphorene.and it makes the contact between the black phosphorus and carbon materials and the electrolyte more fully,thereby further improving the large-current discharge performance of the composite material.After 1000 cycles at 1000 m A/g current density,the BP/HPC anode material shows a reversible capacity of 350 m Ah/g,and after the 10 th cycle is stabilized,the BP /HPC anode material has a coulomb higher than 98% effectiveness.(3)During the charging and discharging process,black phosphorene gradually distributed evenly on the hollow porous carbon,so that it is more fully in contact with the electrolyte,which will improve the utilization of black phosphorus.And under the effect of chemical bonds and hollow porous structure,black phosphorene can maintain good electrical contact with the current collector,fully perform electrochemical reversible reactions,and f urther increase the capacity of the composite material.After 1000 cycles at a current density of 1000 m A/g,the specific capacity of the BP/HPC anode material increased f rom 300 m Ah/g to 350 m Ah/g,and its capacity was nearly double that of the HPC anode.(4)By comparing the electrochemical performance of BP/HPC anode materials with different content of black phosphorene,the composite material with the content of black phosphorene of about 15 wt% has higher utilization rate of black phosphorene,better large-current discharge performance and better economy.Compared with carbon anode material,it has more capacity advantage under high current.And compared with black phosphorus-based anode material,its cycle performance is excellent,and it also has good reversible capacity under high current. |
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