my country has made a breakthrough in 12V23A battery interface issues, providing new ideas for solid-state battery preparation

　　Lithium batteries (LIB) are widely used in portable electronic devices, electric vehicles and other fields. However, safety issues such as low energy density and easy leakage and flammability make LIB difficult to meet contemporary needs. Solid-state batteries (SSB) use safer solid-state electrolytes (SSE) instead of liquid organic electrolytes to avoid electrolyte leakage and circumvent the flammability problem of electrolytes. Solid-state batteries can physically block lithium dendrites or make them after modification. Lithium deposition is more uniform, so lithium metal can be used as the negative electrode, which is considered to be one of the most promising portable energy storage systems in the future.

　　Solid electrolytes generally include inorganic oxide ceramics, sulfides, organic polymers, hydrides and thin film solid electrolytes LPON. Among them, inorganic oxide ceramics mainly include garnet type LLZO, NASION type, and perovskite solid electrolytes. Inorganic oxide ceramic solid electrolytes not only have high conductivity, which can reach 10-3S/cm, but also have a wide electrochemical window. However, due to the rigidity and brittleness of ceramic SSE, interface problems are a major factor hindering the practical application of SSB; solids in SSB -The lithium ion transport kinetics at the solid interface (between solid electrolyte particles and between solid electrolyte and electrolytic material particles) is much worse than the liquid-solid interface of traditional LIB, thus limiting the active material loading capacity and rate of SSB performance. Regarding the interface problems of inorganic ceramics, taking LLZO solid electrolyte as an example, many research groups at home and abroad have made a lot of efforts on its interface. LLZO has no contact with metallic lithium due to surface products such as lithium carbonate and lithium hydroxide on its surface. Wetting, such as plating amorphous silicon, Ge, Sn, Al2O3, etc. on the surface of LLZO to improve contact with metallic lithium. However, there is little work to improve the interface with the positive electrode. Some have introduced gel polymer electrolytes, and some have directly sintered LLZO and the positive electrode together. However, this still introduces flammable electrolyte or unstable cycle performance. Moreover, the sintering of dense LLZO requires high temperature, and the process is cumbersome and energy-consuming. Therefore, developing a method that can simultaneously improve the LLZO grain boundaries and the positive and negative electrode interfaces has important scientific research and industrial value.

　　Recently, Professor Pan Feng's research group at the School of New Materials, Peking University Advanced Research Institute, designed a new type of electrochemically stable MOF ion conductor to address the solid-solid interface problem of solid-state batteries. Combining it with LLZO effectively improved the Li ion migration at the interface. This ionic conductor (Li-IL@MOF, named LIM) is a mixture of porous MOF and lithium-containing ionic liquid (Li-IL). As the ion conductive agent of SSB, Li-IL can directly contact the surface of LLZO particles through the open pores of the MOF body, which can convert the unstable solid-state contact into a nano-wetting interface and promote lithium ion transport. The preparation method is to simply mix LLZO powder with 20% LIM, and then press it into tablets using a 12mm diameter mold in a glove box applying a pressure of 8T. The mixed SSE exhibits high ionic conductivity at room temperature (1×10 -4s/cm), has a wide electrochemical window of 5.2V, and has good matching with Li metal anode. When ion conductors are mixed and assembled into SSBs with LiCoO2 (LCO) and LiFePO4 (LFP), an effective Li+ transport network can be established inside the battery, allowing for very high active material loadings (15.9 and 12.4mg/cm2). At room temperature of 25°C, long-term cycle stability at a low rate of 0.1C can be achieved. This work was recently published in NanoEnergy (201849, 580p, impact factor 12.34), a top international journal in the field of materials and energy.

　　This method of designing novel ionic conductors by loading ionic liquids containing lithium ions into MOF hosts and using them in LLZO-based solid-state batteries to reduce interfacial resistance is important for improving the impedance between the solid-state electrolyte and the positive and negative electrodes. It has important reference significance, and the ion conductive agent with nano-wetting interface also provides new ideas for the preparation of solid-state batteries.

　　Under the guidance of Professor Pan Feng, this work was completed in close collaboration with the team by postdoctoral fellow Wang Ziqi and doctoral student Wang Zijian from the School of New Materials, Peking University Shenzhen Graduate School. The smooth development of this work was supported by the National Major Project of All-Solid-State Batteries Based on Materials Genome, the National Natural Science Foundation, and the China Postdoctoral Science Foundation.

Read recommendations:

Lithium Battery GN72120

Brief introduction of Li ion battery

Advantages and disadvantages of lithium manganese acid batteries

702535 battery Vendor

18650 battery 3.7v 3500mah