All solid-state battery quietly start become industrialization in domestic market

All solid-state battery quietly start become industrialization in domestic market

Among further exploration on energy density of power batteries,  all-solid-state batteries is a trend and world-renowned car companies such as Toyota and BMW have made investments in this field.

At present, the power battery for industrialization is usually a liquid battery, and a liquid material used as an electrolyte. All solid-state batteries, as the name implies, use solid materials as electrolytes. Related electrolyte materials generally have three major categories of polymers, oxides and sulfides. In general, the positive and negative materials are the same, with a liquid electrolyte, the energy density is better than with a solid electrolyte. However, from the pre-accumulation and progress of the industry and research community, the all-solid lithium battery using solid electrolyte and lithium metal anode material has great commercial prospects. If the negative electrode material does not contain metallic lithium, in the strict sense, it should called "lithium ion battery". (Part of the other chapters of this article, the use of the industry's colloquial use of "lithium batteries" instead of "lithium-ion batteries.")

According to Xu Xiaoxiong and Li Wei, on December 25, 2017, the "Corporate Name for All-Solid Lithium Batteries" published by WeChat public account "Energy Storage Science and Technology", the cathode materials of all solid-state batteries generally use composite electrodes, including electrode activity. Substance, solid electrolyte, conductive agent, the industry is more common for LiCoO2, LiFePO4, LiMn2O4 research, late development of high nickel layered oxide, lithium-rich manganese-based and high-voltage nickel-manganese spinel-type positive electrode, or lithium-free new type Cathode material. The negative electrode materials mainly include metal lithium, carbon negative electrode and oxide, each having a length, and the metal lithium negative electrode material is one of the most important negative electrode materials for all solid lithium batteries due to its high capacity and low potential.

As mentioned above, the theoretical lithium intercalation capacity of graphite used as the mainstream negative electrode material for power batteries is 0.372 Ah/g; while the theoretical specific capacity of metallic lithium is as high as 3.86 Ah/g. Therefore, the use of metallic lithium as the negative electrode material theoretically greatly increases the energy density of the battery. As mentioned in the article "Corresponding to the All-Solid Lithium Battery", the all-solid-state lithium battery using metallic lithium as the negative electrode material is expected to have an energy density of 300-400 Wh/kg or even higher.

The all-solid-state battery replaces the organic electrolyte with an inorganic solid electrolyte. In addition to improving the energy density of the battery, it also helps to improve battery safety and cycle life. However, there are still some practical difficulties in the process of industrialization. For example, the compatibility of metallic lithium with solid electrolytes is poor, which affects the performance of metallic lithium anode materials. In recent years, the research community and the industry have carried out a lot of work, in order to realize the industrialization of solid-state batteries at an early date. In China, many research institutes under the Chinese Academy of Sciences (including China University of Science and Technology), Beijing University of Science and Technology, Beijing Nonferrous Metals Research Institute and other scientific research institutions have achieved certain results in the research of solid-state batteries.

Figure 53 shows the improvement of the design of solid-state lithium battery proposed by Ningbo Institute of Materials, Yaoxia Yin, Chinese Academy of Sciences: Li10GeP2S12 with high lithium ion conductivity and Li7P3S11 with stable lithium metal to construct a double electrolyte heterostructure to realize metal lithium anode in solid state battery. Applications. In addition, the team used nanostructured multi-metal sulfide Cu2ZnSnS4 as the positive electrode active material, which significantly inhibited the high interfacial impedance caused by the space charge layer effect of the oxide positive electrode and the sulfide electrolyte. At the same time, the composite graphene builds an electron channel, effectively improving its Cyclic stability, and excellent rate performance, can still maintain discharge specific capacities of up to 544.6 and 233.9 mAh/g by cycling 100 and 300 cycles at current densities of 100 and 1000 mA/g, respectively.

It is gratifying to note that in the industry, mass production of solid-state batteries has achieved important breakthroughs in 2017. If successful, it will promote the further upgrading of China's power battery performance.

Yanfeng Lithium disclosed in the 2017 Interim Report that the company introduced a number of high-end R&D personnel for power batteries in the first half of 2017, including Dr. Xu Xiaoxiong. Dr. Xu Xiaoxiong is an authoritative expert in the field of all-solid-state lithium batteries. He served as the "all-solid-state lithium-ion energy storage battery" in the "12th Five-Year" new energy field of the Ministry of Science and Technology, and the head of the National 863 Program, as well as the long-term power battery of the Chinese Academy of Sciences. Project leader. The company announced on December 6, 2017 that Zhejiang Feng Li, a wholly owned subsidiary, would invest in the development of a first-generation solid-state lithium battery with an annual output of 10,000 watts (100 MW) with its own funds of no more than 250 million yuan. The trial production line will carry out the promotion and market launch of the first generation of products in the new energy vehicle users. The construction period of the project is 2 years.

Guoneng Battery disclosed in its official WeChat public account that it established Henan Pingmei Guoneng Lithium Battery Co., Ltd. in Henan Xinxiang on October 12, 2017 with China Pingmei Shenma Group. According to the plan, the project will build a total of 10GWh all-solid-state lithium-ion power batteries. The first-phase 1GWh all-solid-state lithium-ion power battery project will invest 500 million yuan and expected to complete by the end of 2018. After the completion of the project, it will form the world's first fully automatic solid-state lithium-ion battery production line, change the current international lithium-ion battery industry structure, promote the strategic goal of the 13th Five-Year Plan of National energy battery, accelerate the construction of a new industrial system, and bring high-end to the industry. The field is constantly moving forward.

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