With the rapid development trend of smart wearable devices, pure electric vehicle industry chain, etc., the "high capacity" specifications for rechargeable batteries are also continuing to improve. Using lithium metal as the negative levelHigh capacity lithium battery, has a capacity development potential that is 10 times higher than that of traditional lithium batteries, but it also has potential safety risks.

We learned from Hunan Normal University that a scientific research result on the issue of "lithium dendrites" by Jiang Hanqing Group of Ohio State University, Tang Ming Group of Rice University, and Duan Huigao Group of the same school is expected to help solve this type of "high-energy" The safety "troubles" of high-capacity lithium batteries. This result was recently published in the international power and energy publication Nature Energy.

As the cathode material of traditional high-capacity lithium batteries, high-purity graphite has a storage capacity of 380mAh\/g. However, this is far less than the theoretical specific capacity of lithium metal of 3860mAh\/g. Therefore, lithium metal is more suitable for high-capacity lithium batteries. An ideal battery cathode material. However, in the early days of rechargeable batteries that used lithium metal as the negative level, a network structure of metallic lithium, known as "lithium dendrites," occurred during the charging process of the battery. This may cause internal short circuit failure in the rechargeable battery or even An explosion is a potential safety hazard.

In order to solve the problem of lithium dendrite growth, academic circles have proposed various solutions. These include adding organic preservatives to high-capacity lithium battery electrolytes or using solid electrolytes to inhibit the formation of dendrites. Previous Soon, the research group's discovery of the lithium dendrite problem is expected to help "split" the formation of lithium dendrites from a new and upgraded perspective.

Jiang Hanqing introduced that they found that compressive stress is common during the metal deposition process. The group deposited a copper film on the prepared soft substrate as a current collector, assembled the electrodes into a rechargeable battery, and developed high-capacity lithium batteries under a microscope. Battery charging. It was observed that after charging the battery for a period of time, a one-dimensional wrinkle structure suddenly appeared on the copper film. Through the unbalanced wrinkles of the copper film, the stress on the flexible substrate was greatly released. This confirmed the pressure on the surface of the electrode. Stress can indeed drive the growth and development of lithium dendrites. In addition, they studied the morphology of deposited lithium by depositing lithium metal on copper ingots and soft base current collectors, and confirmed that stress release can effectively avoid the formation of dendrites.