New lithium battery anode material technology without binder

by:CTECHi     2021-08-04

In the process of preparing the negative electrode of lithium ion battery, the proportion of the binder in the electrode is generally between 3% and 5%. If the electrode preparation process does not require a binder, the capacity of the electrode can be significantly increased. Improve the energy density of the battery. Moreover, the binder is usually an insulator, which will hinder the transfer of ions in the electrolyte, thereby affecting the electrochemical performance of the battery. Therefore, it is necessary to design electrode materials that do not require a binder.

Recently, scientists have designed many new electrode materials that do not require binders or current collectors. Among them, single-walled carbon nanotube (SWCNT) films have high specific surface area, high electronic conductivity and mechanical stability. It has attracted much attention in the design of lightweight and flexible electrodes.

Figure 1. Synthesis mechanism diagram of MoSe2/SWCNTs composite material.

Recently, Song Li of the University of Science and Technology of China and others synthesized MoSe2/SWCNTs composite material by a simple solvothermal method, which is used as a lithium-ion battery negative electrode without a binder, showing superior electrochemical performance. This result was published in the international journal ACS Nano.

Figure 2.1 The electrochemical performance of T-MoSe2/SWCNTs composite material: (a) charge and discharge curve diagram; (b) cycle performance diagram; (c) rate performance diagram; (d) Impedance diagram.

Figure 3.1 The electrochemical process mechanism diagram of T-MoSe2/SWCNTs electrode.

As a lithium-ion battery negative electrode, 1T-MoSe2/SWCNTs shows good lithium storage performance. At a current density of 300mA/g, after 100 cycles of cycles, the capacity is still as high as 971mAh/g, with almost no capacity degradation. Under the high current density of 3000mA/g, the capacity is 630mAh/g, which reflects the superior rate performance.

Mechanism explanation

(1) Vertically grown 1T-MoSe2 nanosheets with large interlayer spacing are beneficial to the deintercalation of lithium ions and provide more active sites;

(2)1T-MoSe2 grows on the surface of SWCNTs to form C−O−Mo bonds, which is conducive to rapid electron/ion transfer;

(3) The gap between 1T-MoSe2 and SWCNTs The C-O-Mo bond ensures the stability of the material and alleviates the problem of volume expansion during charging and discharging.

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