The co-utilization of silicon(Si) and graphite(G) has been considered as the preferred strategy to achieve high energy density anode materials,but the effective synergistic integration of Si and graphite is still a ch...The co-utilization of silicon(Si) and graphite(G) has been considered as the preferred strategy to achieve high energy density anode materials,but the effective synergistic integration of Si and graphite is still a challenge and it is necessary to find a scheme to accommodate the large-scale production of Si/graphite anodes.In this work,silicon cutting waste from the photovoltaic industry was used as raw material,mixed with graphite,pitch,and polyvinylpyrrolidone,and subjected to high-energy ball milling.The mixture was then heated in an Ar atmosphere for the carbon coating,and the resulting Si/graphite/carbon(Si/G/C) composite was etched to remove the thicker SiOx layer formed on the Si surface to allow the pores between the Si and the carbon matrix to obtain Si@voids/G@C.Benefiting from the integrated structural design and the significantly enhanced electronic conductivity,the Si/G@voids@C composite exhibited the first dischargespecific capacity of 2530 mAh·g^(-1) with an initial coulombic efficiency(ICE) of 86.7%,and the remaining capacity exceeded 1000 mAh·g^(-1) after 550 cycles at 1.5A·g^(-1).Notably,full lithium-ion batteries with a Si/G@voids@C anode and LiFePO_4 cathode delivered a stable capacity of 140 mAh·g^(-1).The synthesis method is facile and cost-effective,providing an integration strategy for Si and G with a potential scheme for large-scale commercial applications.展开更多
There were many hypotheses about the spheroidizing mechanism of nodular graphite.Among them, Chen Sysen’s theory was the most perfect. He considered: in the liquid cast iron, sometimes the groups of carbon atoms, app...There were many hypotheses about the spheroidizing mechanism of nodular graphite.Among them, Chen Sysen’s theory was the most perfect. He considered: in the liquid cast iron, sometimes the groups of carbon atoms, appearing with the form of large planes of molecules, get together and sometimes they separate away. When the temperature decreases below the liquidus, the groups of carbon atoms (large planes of molecules), which occasionally get together, will form a polyhedron. The more the faces of the polyhedron are, the smoother the ball will be. This polyhedron is exactly the nucleus of nodular graphite.展开更多
In this work, the influence of graphite on the ball-milled TiC, was studied. The results show that the lattice parameter of TiC, is increased when TiC, particles are ball-milled with graphite, which indicates a decrea...In this work, the influence of graphite on the ball-milled TiC, was studied. The results show that the lattice parameter of TiC, is increased when TiC, particles are ball-milled with graphite, which indicates a decrease in the concentration of carbon vacancies in the TIC,. It is considered that this decrease in the concentration of carbon vacancies results from the diffusion of carbon atoms from graphite into the TiCx. When the TiCx is ball-milled with more graphite, the effectiveness of the ball-milling is better, and the diffusion process of carbon becomes much easier. Furthermore, besides diffusion into the TiCx, some graphite has transformed into amorphous carbon after the ball-milling.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51974143,52274408,5220041313,52164050 and 51904134)Major Science and Technology Projects in Yunnan Province (Nos.202102AB080016,202103AA080004 and 202202AB080010)+3 种基金Yunnan Fundamental Research Projects (No.202201AW070014)Yunnan Ten Thousand Talents Project (No.YNWR-QNBJ-2018-111)Yunnan High-level Talent Project (No.YNQR-GCC-2019-010)the Program for Innovative Research Team in University of Ministry of Education of China (No.IRT_17R48)。
文摘The co-utilization of silicon(Si) and graphite(G) has been considered as the preferred strategy to achieve high energy density anode materials,but the effective synergistic integration of Si and graphite is still a challenge and it is necessary to find a scheme to accommodate the large-scale production of Si/graphite anodes.In this work,silicon cutting waste from the photovoltaic industry was used as raw material,mixed with graphite,pitch,and polyvinylpyrrolidone,and subjected to high-energy ball milling.The mixture was then heated in an Ar atmosphere for the carbon coating,and the resulting Si/graphite/carbon(Si/G/C) composite was etched to remove the thicker SiOx layer formed on the Si surface to allow the pores between the Si and the carbon matrix to obtain Si@voids/G@C.Benefiting from the integrated structural design and the significantly enhanced electronic conductivity,the Si/G@voids@C composite exhibited the first dischargespecific capacity of 2530 mAh·g^(-1) with an initial coulombic efficiency(ICE) of 86.7%,and the remaining capacity exceeded 1000 mAh·g^(-1) after 550 cycles at 1.5A·g^(-1).Notably,full lithium-ion batteries with a Si/G@voids@C anode and LiFePO_4 cathode delivered a stable capacity of 140 mAh·g^(-1).The synthesis method is facile and cost-effective,providing an integration strategy for Si and G with a potential scheme for large-scale commercial applications.
文摘There were many hypotheses about the spheroidizing mechanism of nodular graphite.Among them, Chen Sysen’s theory was the most perfect. He considered: in the liquid cast iron, sometimes the groups of carbon atoms, appearing with the form of large planes of molecules, get together and sometimes they separate away. When the temperature decreases below the liquidus, the groups of carbon atoms (large planes of molecules), which occasionally get together, will form a polyhedron. The more the faces of the polyhedron are, the smoother the ball will be. This polyhedron is exactly the nucleus of nodular graphite.
基金supported by the National Natural Science Fundation of China (grant No. 51071097)the Fundamental Research Fund for the Central Universities of China (grant No. 11QG67)
文摘In this work, the influence of graphite on the ball-milled TiC, was studied. The results show that the lattice parameter of TiC, is increased when TiC, particles are ball-milled with graphite, which indicates a decrease in the concentration of carbon vacancies in the TIC,. It is considered that this decrease in the concentration of carbon vacancies results from the diffusion of carbon atoms from graphite into the TiCx. When the TiCx is ball-milled with more graphite, the effectiveness of the ball-milling is better, and the diffusion process of carbon becomes much easier. Furthermore, besides diffusion into the TiCx, some graphite has transformed into amorphous carbon after the ball-milling.
