Through The Nano-pores To Limit The Uniform Distribution Of Lithium Ions

- Jan 09, 2017-

In order to meet the energy density requirements of rechargeable batteries, a large number of studies focused on high specific capacity battery systems, such as: silicon, tin, lithium metal, lithium-sulfur batteries. Lithium metal due to its high theoretical capacity, low electrochemical potential is very promising anode material. However, due to its safety and efficiency reasons, it is difficult to apply to commercial lithium batteries. During the repeated deposition and dissolution of the lithium metal, the growth of the lithium dendrite inevitably occurs on the surface of the negative electrode, thereby piercing the separator and causing the internal short circuit of the battery. The high specific surface area of lithium dendrite and electrolyte can promote the formation of SEI film, leading to the rapid decrease of Coulomb efficiency due to the increase of internal resistance.

Recently, the CuiYi group has developed a novel method for controlling lithium dendrite using nano-confinement effects, which can control the uniform deposition, nucleation and growth of lithium ions. As shown, lithium can be uniformly deposited by coating a layer of nanoporous polymer with a vertical array. This high aspect ratio nanochannel allows the anode to be divided into small regions where the lithium ions can grow in the vertical rather than the horizontal direction. In this way, it is possible to control the relative uniform deposition, nucleation and growth of the lithium ions on each channel without causing individual super long dendritic growth.

At the same time, due to its fixed pore structure, it is possible to effectively control the volumetric expansion caused by lithium deposition. In addition, the porous polymer film can be in intimate contact with the current collector, avoiding the loss of the deposited lithium metal.

In addition, the researchers propose that more research is needed to stabilize the cycle of lithium metal anode under high current density and commercial surface capacity, such as lithium-ion battery, lithium-sulfur battery and other next-generation power battery. The encapsulation of nanoscale vertical vias can be easily scaled up and laid the foundation for further commercial applications.