Research On Foam Lithium Metal Anode Of Secondery Lithium Battery

The lithium metal anode possesses of high theoretical specific energy density, low electrode potential and high electrochemical reversibility. However, the formation of dead lithium and dendrinic on the surface of the lithium anode in the process of cycle leads to poor cyclability and security performance. So how inhibit the formation of dendrinic and dead lithium and improve the cyclability and safety performance are the primary content of this article.This article uses the method of two cathode electrochemistry deposit to make large specific surface foam lithium anode materials with the foam Ni and foam Cu as deposit matrix. And then the electrochemical performance and the efficiency of it used in lithium secondary battery were systematically studied, as well as the the mechanism of the new lithium electrode was analyzed.The preparation parameters of the foam lithium made by the method of electrodeposit were: the current density was 1mA·cm-2, the deposit capacity was 20mAh·cm-2. The foam lithium has several times larger surface than lithium foil. In the same charge and discharge current conditions the real current densities on the surface will be decreased. The deposition and dissolution efficiency show that the meam cycling efficiency of the foam Li was 94.2%, but only 46.7% for foil Li. In the same time, the EIS impedance spectroscopy analysis show that in the same charge and discharge current conditions, with the increasing cycles number of the foam lithium impedance increased slightly, the resistence increased from 160? to 260?, but lithium metal foil surface impedance was significantly increased, the resistence increased from 2500? to 25000 ?. By the analysed of the charge-discharge curve, the charge platform of the foam lithium anode was lower and the discharge platform was higher than lithium foil anode. At 4mA·cm-2 current density, the charge/discharge efficiency was also above 95%, and the capacity was above 95% compare with initial capacity, but the foil Li was below 95% and 40%, so the capacity of battery was improved.The results show that the foam lithium mechanism as follows: large real surface leads to little current densities, and low current densities restrain the grows of the dendrinic and dead lithium, this made the foam lithium anode appeared excellent interface stability, high charge-discharge efficiency, long battery cycle life and surface morphology have been improved. In the same time foam lithium three-dimensional structure reduces the contact area between the anode and the cathode, the dendrinic grows inside the foam lithium, which reduce the occurrence of a short-circuit, improved the safety of lithium metal secondary battery.