Lithium-ion batteries have been widely used in portable electronic devices, electric vehicles and other fields because of their high specific energy. However, for larger-scale energy storage, the safety performance of current commercial lithium-ion batteries based on organic electrolytes is difficult to meet the requirements. In recent decades, scientists have made great efforts to improve rechargeable lithium-ion batteries based on organic electrolytes. However, the organic electrolytes currently developed have great limitations in terms of electrochemical stability and thermal stability. In view of this, the researchers proposed the use of inorganic solid electrolytes instead of liquid electrolytes in order to finally solve the hidden safety problems.

Interface stability is one of the important factors affecting the chemical performance of solid-state lithium batteries. In all-solid-state lithium batteries using sulfide materials as electrolytes, although the lithium ion conductivity of the sulfide solid electrolyte has reached the level of liquid electrolytes, the battery The capacity of the battery is still not high, and the cycle and rate performance are far lower than the traditional organic electrolyte battery. After in-depth research, the researchers found that the most critical factor that determines the battery capacity and high rate performance is the positive electrode/sulfide solid electrolyte interface.

In response to the various problems existing between sulfide solid electrolytes and various cathode materials, researchers have proposed a variety of strategies to improve interface stability.

Electrolyte modification

Since the solid electrolyte is in direct contact with the positive electrode material, the stability can be improved by adjusting the composition of the solid electrolyte, thereby effectively suppressing the occurrence of space charge layer and interface reactions. In addition to high ionic conductivity and low electronic conductivity, the solid electrolyte should also have similar chemical potential and small mismatch with the positive electrode material. The most commonly used strategy to improve the stability of sulfide solid electrolytes is to partially replace sulfur with oxygen, because the lattice mismatch between oxygen ions and the oxide positive electrode is low, and the electrochemical stability of oxides is high, so oxygen is used to partially replace sulfur. Oxygen can be inhibited from entering the sulfide electrolyte from the oxide cathode, so oxygen doping can greatly inhibit the interface reaction of sulfide-based solid-state batteries.

Ball milling

Ball milling is currently the most commonly used method of mixing electrolyte and cathode materials. Many current studies show that through reasonable parameter control, ball milling can effectively reduce the interface impedance between the active material and the solid electrolyte. In the process of ball milling, the raw materials will undergo mixing, powdering, amorphization and solid phase reaction processes, and finally a homogeneous composite positive electrode is formed. The development of high-energy ball milling has also greatly promoted the preparation of amorphous sulfide solid electrolytes, which can effectively reduce the grain boundary impedance in solid-state batteries due to their soft texture. Ball milling can promote the limited solid-phase reaction between the solid electrolyte and the surface of the active material to form a mesophase buffer layer, which can well inhibit the space charge layer or interface reaction.

Artificial electrolyte membrane formed at the interface

On the basis of optimizing the electrolyte, the preparation of an artificial solid electrolyte membrane can also effectively inhibit the negative electrode interface reaction and dendrite growth. The artificial solid electrolyte membrane can avoid the direct contact of high-activity metal lithium with the solid electrolyte, thereby avoiding adverse side reactions at the interface.

All solid-state lithium batteries have attracted extensive attention from researchers and industries from all over the world due to their huge potential in terms of safety performance and energy density. Thanks to the huge breakthrough in ionic conductivity, all-solid-state batteries based on sulfide solid electrolytes are considered one of the most promising next-generation energy storage devices. However, there are still many problems to be solved urgently. The optimization of the dielectric, the exploration of positive electrode materials, the positive electrode/electrolyte interface, the negative electrode/electrolyte interface, etc. will solve these problems one by one, and the time for solid-state batteries to shine in the field of energy storage has come.

Reference materials:

Li Li, Chen Lin, etc. Research progress and industrial application of sulfide solid electrolyte

Wu Jinghua, Yao Xiayin. Research progress on interface characteristics of all solid-state lithium batteries based on sulfide solid electrolytes

China Powder Network.

2020 National Quartz Conference and Exhibition

2020 National Quartz Congress & Exhibition

From the first "Quartz Fine Processing and Application Technology Exchange Conference" held in 2017 to the "2019 National Quartz Conference" in 2019, the quartz industry chain conference held by China Powder Network has been successfully held for 3 sessions, bringing together domestic and foreign The participation of many enterprises engaged in quartz mineral processing is an industry conference that attracts special attention in the quartz industry.

With the gradual control of the epidemic, the production order will gradually resume in the second half of the year. At the request of industry experts and new and old customers, the "2020 National Quartz Conference" is scheduled to be held on November 26-27, 2020 at Howard Johnson Nanshan Hotel, Bengbu, Anhui , The organizing committee of the conference strives to achieve greater improvement in scale and communication effects, and better promote the development of the quartz industry through this platform.

With the theme of "Efficient Utilization, High-end Breakthrough", this conference hopes to discuss with industry colleagues on how to maximize the value of quartz ore resources from raw ore analysis, market positioning, tailings treatment and other aspects. The development prospects of high-end products such as pure quartz, electronic grade silicon powder, spherical silicon powder, etc. The conference sincerely welcomes domestic quartz industry experts, scholars, business representatives, and technical personnel to actively participate in the conference.

Information source: Powder Network

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