Tsinghua Chemical Engineering Zhang Qiang Test Group has made progress in high safety compound lithium metal negatives

Tsinghua Chemical Engineering Zhang Qiang Test Group has made progress in high safety compound lithium metal negatives

Recently, Professor Zhang Qiang, Department of Chemical Engineering, Tsinghua University, published the paper “Coraloidcarbonfibuser-based CompleteLithiumanodeForrobustLithiumMetalbatteries”, which was published in the well-known period “Joule” in the well-known period “Joule” (CORALLOIDETLIBUSTLITHIUMMETALBATERIES), reported Important progress made in the field of high safety and high capacity composite lithium metal negatives. The study was selected as the current cover article in the “Joule” and published a cover picture..

Metal lithium has extremely high theoretical specific capacity and lowest redox electrode potential, thus becoming the next generation of high-energy density energy storage batteries (next generation solid lithium ion batteries, lithium sulfur batteries, lithium-empty batteries, etc.) the most ideal negative material. However, the unstability of the dendride and lithium and electrolysis mask during metal lithium charging process severely reduces the cycle efficiency of lithium metal batteries, shortens the battery life, and even brought a certain degree of safety hazards, serious Hold the development of lithium metal batteries.

The cover picture shows the “compound lithium metal negative” design idea, based on the composite lithium metal negative electrode of lithium carbon fiber, can be sailed in the “ocean” of the molten “ocean”. Recently, researchers have proposed a number of metal lithium-based negatives based on conductive carbon skeletons or metal skeletons..

However, many such skeletons do not have a pre-composite metal lithium, but a half-cell test as a lithium-free concentration fluid.. Such a non-lithium concentration fluid is difficult to apply directly to the entire battery.

Therefore, how to efficiently composite the metal lithium in advance to the current fluid structure, forming a high-performance composite lithium metal negative electrode that can be directly assembled as a full battery has become the focus of research.. Professor Zhang Qiang, Tsinghua University, studied the urgent needs of metal lithium ion batteries about composite electrodes, proposed a composite lithium metal negative electrode of coral carbon fiber melt.

The surface of the carbon fiber skeleton (CF) is modified to the surface of the lithium, which can quickly suck the liquid molten metal lithium, which can quickly suck the carbon fiber skeleton (CF / AG) having a silver coating layer, thereby producing high performance Composite lithium metal negative electrode (CF / Ag-Li). On the one hand, any conductive skeleton can modify the lithium conductive skeleton of irons-liquid molten lithium, and on the other hand, it can also reduce the deposition of metal lithium, and obtain excellent cycle stability at high magnification. “Dead Lithium” circulating topography.

Through the observation experiment with the in situ metal, it is found that it is difficult to form a dendritic crystal in the composite structure.. The proposed composite lithium metal negative electrode can be more than 160 laps at a very low polarization of 10 mACM-2 and 10 mAhcm-2 extreme harsh conditions.

Compared to conventional metal lithium negative electrode, the composite lithium metal negative electrode can withstand extreme surface current density and surface capacity circulation, showing high safety characteristics. Composite lithium metal negative electrode of coral carbon fiber, a composite metal negative electrode and a lithium tester and lithium iron phosphate positive electrode, and a lithium sulfur battery and a lithium iron ion battery. The lithium phosphate ion battery can be stably circulated at 1.

0C magnification, and the initial discharge capacity of the lithium sulfur battery is from 781 mAhg-1, and maintains a high capacity cycle over 400 laps.. The working electrically conductive skeleton plated lithium-plated ribbon lithium-plated ribbon can generally be a composite metal lithium negative design and preparation based on conductive skeleton, and silver plating layer can achieve high-efficiency preset metal lithium composite, and achieve non-deny, no “dead Lithium “cycle appearance, and then obtains excellent electrochemical properties in all-battery systems such as lithium sulfur cells, enhances the safety of energy storage system systems.


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