高性能钾离子电池合金类负极材料的制备及研究

PREPARATION AND STUDY OF HIGH PERFORMANCE POTASSIUM ION BATTERY ALLOY ANODE MATERIALS

龚志刚

11930272

硕士

材料工程

谷猛

2021-05-20

2021-06-24

南方科技大学

深圳

合金类负极材料由于其优异的性能，在钠离子电池和锂离子电池中得到了广泛的研究。其独特的离子存储机制与可逆的合金化反应，有望在钾离子电池中获得较高的比容量。然而，在电化学反应过程中合金类负极材料的体积膨胀和导电性差严重限制了其应用。虽然科学家们采取各种各样的方法进行改性，但是在电池中容量衰减的原因、结构的变化和反应机理还需要进一步深入研究。本文利用两种不同的合成方法使Sn4P3纳米颗粒和碳结合形成复合材料来研究其物理和电化学性能，具体要研究如下：利用机械球磨的方法制备Sn4P3@C复合材料。结合XRD、SEM和TEM等表征手段，发现科琴碳的超大比表面积为Sn4P3颗粒提供了宽广的附着点，减少团聚，有效的抑制其体积膨胀。电化学分析表明，在50 mAg-1的电流密度下，第二圈的放电容量达到825 mAhg-1。循环到90圈时，放电容量仍保持在770 mAhg-1。采用静电纺丝技术和水热反应相结合，巧妙地的把Sn4P3纳米颗粒封装到碳纤维中，并且碳纤维形成的三维网络结构不仅提供了电子运输通道，而且也抑制了体积膨胀。电化学表明，在50 mAg-1的电流密度下，Sn4P3@CNFs-10%复合材料循环200圈后，可逆容量仍保持在458 mAhg-1，倍率性能更优。

Alloy anode materials have been widely studied in sodium ion batteries and lithium ion batteries due to their excellent properties. Because of its unique ion storage mechanism and reversible alloying reaction, it is expected to obtain higher specific capacity in potassium ion batteries. However, the volume expansion and poor conductivity of alloy-like anode materials in the electrochemical reaction process seriously limit their applications. Although scientists have adopted a variety of methods for modification, the reasons for capacity decay, structural changes and reaction mechanisms in the battery still need to be further studied.In this paper, Sn4P3 nanoparticles were combined with carbon to form composites using two different synthesis methods to study their physical and electrochemical properties. The specific research is as follows:Sn4P3@super carbon composites were prepared by mechanical ball milling. By means of XRD, SEM and TEM, we found that the large specific surface area of Cochin carbon provided a broad adhesion point for Sn4P3 particles, reducing agglomeration and effectively inhibiting its volume expansion. Electrochemical analysis showed that the discharge capacity of the second cycle reached 825 mAhg-1 at the current density of 50 mAg-1. The discharge capacity remained at 770 mAhg-1 after 90 cycles.By combining electrospinning technology with hydrothermal reaction, Sn4P3 nanoparticles were encapsulated into carbon fibers, and the three-dimensional network structure formed by carbon fibers not only provided electron transport channels, but also inhibited volume expansion. On the electrochemical surface, at the current density of 50 mAg-1, the reversible capacity of the Sn4P3@CNFs-10% composite remains 458 mAhg-1 after 200 cycles, and the rate performance is better.

钾离子电池 机械球磨 静电纺丝 体积膨胀 合金类负极材料

potassium ion battery mechanical ball mill electrospinning volume expansion alloy type anode materials

中文

独立培养

南方科技大学

龚志刚. 高性能钾离子电池合金类负极材料的制备及研究[D]. 深圳. 南方科技大学,2021.