Views: 30 Author: Site Editor Publish Time: 2022-04-11 Origin: Site
The electric vehicle market is booming, and battery life has become a pain point. The development of high-performance lithium batteries is imminent but how to build high-performance next-generation lithium battery anodes?
Commercial lithium-ion batteries are mainly composed of layered oxide cathodes and graphite anodes.
We compared the mass energy density of different energy storage systems: gasoline has the highest energy density, 5 times the energy density of graphite anode lithium-ion batteries.
Nevertheless, the energy density of next-generation lithium batteries based on lithium metal anodes, including lithium metal batteries, lithium sulfur batteries, lithium air batteries have been doubled.
However, there are many problems with lithium metal anodes,including metal dendrite growth and capacity decay on the surface of metal lithium negative electrode during charge and discharge process, etc.
The short circuit is mainly caused by lithium dendrites. For example, factors such as the uneven concentration of lithium ions on the electrode surface will lead to the growth of lithium dendrites, which will pierce the separator and cause a short circuit.
The capacity decay comes from the reaction between lithium and electrolyte and its own pulverization process. The reactivity of lithium is relatively active, it will react with the electrolyte, consume a certain amount of active lithium, and cause a part of the battery capacity loss. At the same time, the dusting of lithium metal during the charging and discharging process will cause an increase in impedance and consume battery power.
In recent years, research on lithium metal batteries has shown explosive growth.
We also summarize five different lithium anode modification methods.
1. Stabilized lithium-metal powder anode (SLMP)，it can effectively compensate for the irreversible capacity of commercial anode materials such as graphite.
2. Stabilized lithium-metal anode (SLMA), it can reduce the powdering process of lithium metal and suppress dendrites;
3. Deposited lithium-metal anode (DLMA) , it can effectively control the current density on the electrode surface, but the preparation process is cumbersome and complicated;
4. Composite lithium-metal anode (CLMA), It is easier to form a reliable electrode structure and avoid complex preparation processes such as pre-lithiation;
5. Anode-free lithium-metal anode (AFLMA), directly using copper as the anode greatly simplifies the battery fabrication process.
On the whole, the stabilized lithium metal electrode is the most promising and practical electrode; and the stabilized lithium metal powder electrode is the first choice for improving the energy density of the battery.
While the current technology is still a long way from the practical application of lithium metal electrodes. With the development of advanced characterization technology and preparation technology, the working mechanism of lithium metal batteries will be more thoroughly studied. And the production process will be further improved, on this basis, safe and high-energy lithium metal batteries may be expected to be launched soon, enter the market and lead the new energy revolution.