Biomass nanomaterials make lithium metal batteries safer

Lithium metal is considered to be the "holy grail" material for the construction of high specific energy battery electrodes because of its ultra-high theoretical specific capacity and lowest electrode potential. Compared with existing commercial lithium-ion batteries, lithium metal batteries (LMBs) based on metallic lithium as the negative electrode have greatly improved the theoretical energy density of the battery, demonstrating the great potential to meet the needs of emerging industries for high energy density.

Recently, Zhang Qiang, a professor at Tsinghua University, Yuan Tongqi, a professor at Beijing Forestry University, Huang Jiaqi, a researcher at Beijing Institute of Technology, and Maria Magdalena Titiric, a professor at Imperial College London, published a review article in Materials Today Nano Based on the understanding of anode chemistry, the latest research results of lithium metal anode protection strategies based on biomass nanomaterials are introduced, and the future development direction is prospected.

The researchers said that the problems of uncontrolled lithium dendrite growth and unstable SEI film on the metal lithium anode limit the commercialization process of lithium metal batteries. Natural biomaterials have the advantages of low cost, environmental friendliness, and rich structure, and their derived nanomaterials can inherit the excellent characteristics of natural materials, and have great application potential in stabilizing interface SEI and regulating the growth of negative electrode lithium dendrites. .

The article points out that the artificial protective layer of natural biomass polymer film has higher mechanical strength and rich physicochemical characteristics such as functional groups, and has advantages in constructing an artificial protective layer. On the one hand, the growth of dendrites can be suppressed by the high mechanical modulus of natural polymers; on the other hand, the rich polar functional groups in the polymer backbone can also be used to regulate the uniform deposition of lithium ions.

Diaphragm biomacromolecules have a rich pore structure and polar surface functional groups. They are widely used to modify traditional diaphragms or design new biomass-based diaphragms to improve the wettability and ion flux of the diaphragm and achieve lithium ion Efficient electrochemical deposition.

The polymer electrolyte natural biopolymer has rich chemical groups, high mechanical elasticity and chemical stability, and can be cross-linked through physical chemistry or used as a polymer electrolyte carrier to improve the mechanical properties and ionic conductivity of the polymer electrolyte To obtain a highly efficient and stable lithium negative electrode interface.

Nanocarbon materials derived from functional skeleton natural biological materials have the advantages of rich porous structure, high electrical conductivity and diversified structure, and have important application prospects in the construction of functional skeletons or lithium metal anode hosts.

This review builds a bridge between sustainable natural biomass materials and lithium metal anode protection to promote the application of biomass nanomaterials in high energy density LMBs and other advanced energy storage systems.

It is understood that the team of Zhang Qiang has carried out many leading research work in the field of energy material chemistry, especially metal lithium anodes, lithium-sulfur batteries and electrocatalysis. In the field of metal lithium anodes, the team used in-situ methods to study the solid-liquid interface film, and adjusted the deposition behavior of metal lithium through nano-skeleton, artificial SEI, surface solid electrolyte protection film, etc., inhibited the growth of lithium dendrites, and realized metal lithium Efficient and safe use. Related research work has been published in many journals such as "German Applied Chemistry", "Journal of the American Chemical Society", "Advanced Functional Materials" and "Proceedings of the American Academy of Sciences". (Reporter Li Huiyu)