A new strategy for protecting lithium metal anodes with a two-dimensional heterostructure proposed by Dalian Chemical

[ Instrument R & D of Instrumentation Network ] Recently, the team of Wu Zhongshuai of the two-dimensional material and energy device research group of Dalian Institute of Chemical Physics, Chinese Academy of Sciences and the team of Liu Zhongmin and Ye Mao of the Department of Low Carbon Catalysis and Engineering have proposed a two-dimensional mesopore A new strategy of qualitative structure dual-function lithium ion redistribution to obtain a metal lithium anode with high stability, high capacity, and no dendrites.

The increasing globalization of the stone energy crisis has caused researchers to pay more and more attention to clean energy. The development of high energy density batteries and the promotion of long-endurance electric vehicles are one of the important ways to promote clean energy and jointly build green travel. Lithium metal batteries are considered to be the next generation of high-energy batteries due to their high theoretical specific capacity (3860 mAh / g) and low redox voltage (-3.04 V vs. SHE). However, metal lithium anodes have serious lithium dendrites, and have poor cycle performance, low Coulomb efficiency, and safety problems, which seriously hinder the widespread application of lithium metal batteries. Therefore, how to design a reasonable structure, regulate lithium ion deposition behavior, achieve uniform lithium deposition, and extend its cycle life is one of the major bottlenecks in current research on lithium metal battery applications.

In order to solve this problem, the team of Wu Zhongshuai proposed a new strategy for redistribution of bifunctional lithium ion with two-dimensional mesoporous heterostructure, and designed and prepared a new two-dimensional mesoporous polypyrrole-graphene oxide heterojunction new material. The synergistic effect of the ordered lithium ion channels of the mesoporous polypyrrole layer and the nano-sieve of defective graphene oxide achieves a uniform lithium ion distribution and effectively reduces the current density, thereby obtaining high stability, high capacity and no dendrites Lithium metal anode. Lithium symmetric battery (mPPy-GO-Li // mPPy-GO-Li) maintains a high coulombic efficiency (98%) for up to 1000 cycles (2000 h), and has flatness at high current density (10 Ma / cm2) Voltage (70 mV) curve, and no lithium dendrites are generated. The team of Liu Zhongmin and Ye Mao provided electric field simulation calculation support, and proved that the two-dimensional heterostructure can effectively equalize the unstable current fluctuations. The lithium / lithium cobaltate full battery assembled with this negative electrode showed excellent rate and cycle stability performance. This work provides new ideas for constructing a two-dimensional heterostructure of lithium metal batteries with good safety, high specific energy and long life.

The related research results were published in "German Applied Chemistry" (Angew. Chem. Int. Ed.). The above work was supported by the National Key R & D Program Project, the Two Fusion Fund Projects, and the Collaborative Fund Project of the Clean Energy Innovation Institute of the Chinese Academy of Sciences.