The team of Ma Cheng, a professor at the University of Science and Technology of China, and Nan Cewen, a member of the Chinese Academy of Sciences and a professor at Tsinghua University, have made new progress in the research of solid-state electrolytes for lithium batteries. The researchers used spherical aberration corrected transmission electron microscopy to observe the interface between the solid electrolyte and the electrode material and found that an epitaxial interface can be formed between the positive electrode of the lithium-rich layered structure and the solid electrolyte of the perovskite structure. Using this phenomenon, the researchers prepared a composite positive electrode with a rate performance comparable to the traditional slurry-coated positive electrode, which provided a new way of thinking to overcome the bottleneck of the electrode-electrolyte contact difference in solid-state batteries. Related research results were published in Matter, a material journal under Cell Press, with the title of Atomically Intimate Contact between Solid Electrolytes and Electrodes for Li Batteries. The first author of the thesis is Li Fuzhen, a graduate student of the Chinese University of Science and Technology. Traditional lithium-ion batteries use flammable organic liquid electrolytes with limited electrochemical windows, which are generally flammable and difficult to increase energy density. Compared with organic liquid electrolytes, solid electrolytes are mostly non-flammable, which can reduce or even eliminate the risk of battery fires. At the same time, they have a wider electrochemical stability window, allowing the use of higher voltage positive and negative electrode combinations to increase the energy density of the battery. Research in recent years has found many solid electrolytes with excellent performance. However, mainstream electrode materials are also solid substances. If the liquid electrolyte is replaced with a solid electrolyte, it will be difficult to form a close and sufficient contact like the solid-liquid interface between the electrode and the electrolyte, which seriously affects the efficiency of lithium ion transport between the electrode and the electrolyte. This bottleneck is one of the most difficult challenges for solid-state batteries to overcome. The observation of spherical aberration corrected transmission electron microscope provides a new idea for solving this problem. When using electron microscopy to study the perovskite structure solid electrolyte Li0.33La0.56TiO3, the researchers found that the structure of the lithium-rich layered oxide, a high-performance electrode material, can be compared with the structure of perovskite, a widely studied solid electrolyte. An epitaxially grown interface is formed, thereby forming a close and sufficient solid-solid contact at the atomic scale. The researchers further conducted an in-depth analysis of the epitaxial interface between the two, and found that every 15 atomic planes at the interface will form a mismatch dislocation, releasing the accumulated strain. This mechanism has led to the formation of epitaxial interfaces that do not require electrodes and electrolytes to have similar lattice sizes, but can occur widely between a variety of layered structural materials and perovskite structural material systems. Subsequently, the researchers used this conclusion in the actual material preparation, using the layered electrode material 0.54Li2TiO3-0.46LiTiO2 crystal as a template to crystallize amorphous Li0.33La0.56TiO3 to prepare an atomic-level interface-bound electrode-electrolyte Composite cathode material and characterize it. The results show that the solid-solid composite electrode prepared by this method has a sufficient degree of binding between the active material and the electrolyte, which is close to the solid-liquid contact, and its rate performance is not inferior to the solid-liquid composite electrode prepared by the traditional slurry coating technology. The proposed method provides a new idea to overcome the bottleneck of the electrode-electrolyte contact difference in solid-state batteries. The above research was supported by the National Key Research and Development Program of the Ministry of Science and Technology, the National Natural Science Foundation of China, and the China National University of Science and Technology Innovation Team Cultivation Fund. ZSEM main Semiconductor process materials are fluoride etching gases such
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