Graphite Nanosheets are formed by using plasma to peel off graphite, and the refined antimony sulfide (Sb2S3) is compounded on the nanographite under the mechanical and thermal effects of ball milling to achieve high capacity and long cycle life of antimony sulfide-graphite nanometers. Design and preparation of sheet composite anode materials.
Preparation method
Sb2S3 and graphite were put into a ball mill pot at a mass ratio of 1: 1, and at the same time, a ball with a size of 7 mm was added to the ball mill for a period of 6 h to obtain a Sb2S3-C composite anode material. At the same time, Sb2S3 composites with different ball milling times and different mass ratios were compared in the same way.
During the ball milling process, the graphite was peeled by van der Waals' forces in the direction of the combination of plasma and mechanical ball milling, so that graphite was efficiently stripped into graphite nanosheets, and antimony sulfide particles were also refined into nanoscale particles. Further, the antimony sulfide particles are embedded in the graphite nanosheets under the impact of the grinding ball to form a Sb2S3-C composite material.
The structure in which antimony sulfide particles are embedded in the nano-graphite sheet can effectively limit the volume change of the antimony sulfide particles during the deintercalation of lithium, and greatly improve the reversibility of antimony sulfide in the conversion reaction stage, thereby improving antimony sulfide as a lithium ion battery anode material. Cycle performance.
2. Results comparison
From the comparison of the charge and discharge curves, it can be seen that the cycle reversibility of Sb2S3-C after plasma ball milling has been significantly improved; further analysis of its capacity differential curve can be seen that Sb2S3 is refined to nanoscale and embedded in graphite nanometers by plasma ball milling After filming, the capacity retention rate of Sb2S3 in the alloying reaction and transformation reaction phase has been significantly improved.
This is because the volume change of Sb2S3 embedded in the nano-graphite sheet is alleviated during the cycle, so that the Sb / Li2S generated during the conversion reaction can react to form Sb2S3 during the reverse conversion reaction. Therefore, the Sb2S3- C has higher reversible capacity and cyclic stability.
3. Conclusion analysis
The capacity of Sb2S3-C after plasma ball milling is still as high as 638.2mAh / g after 250 cycles, while the capacity of Sb2S3-C without ball milling is only 364.8mAh / g, and its capacity is significantly improved; meanwhile, plasma ball milling The rate performance of the later Sb2S3-C was also significantly improved.
After 500 cycles at a high current density of 1A / g, the Sb2S3-C after plasma ball milling can still maintain a capacity of 498.3mAh / g, and the capacity retention rate is ~ 80%, which realizes the high capacity and long-cycle stability of the battery system. Sex.
It can be seen from the further analysis of the capacity contribution range that Sb2S3-C after plasma milling can contribute a higher reversible capacity in both the alloying reaction and the conversion reaction. Compared with other Sb2S3-C work, plasma ball milling Sb2S3-C composite anode material has obvious advantages in capacity retention.
This is precisely because the plasma ball milling peels graphite to form graphite nanosheets, and at the same time refines antimony sulfide into nanoparticles and embeds them on the graphite sheet. By suppressing the volume change during the Sb2S3 cycle and inhibiting the agglomeration of the active phase, the structure of Sb2S3 in The stability during the cycling process finally achieved the high capacity and long-cycle stability of the Sb2S3-C composite anode material.