Research on high energy density lithium battery made by Ningbo Institute of Materials
Lithium metal secondary batteries are an important development direction of next-generation battery technology that breaks through the energy density of 500Wh/kg, and are facing greater challenges. Compared with traditional lithium-ion batteries, this battery system puts forward new requirements for key materials such as positive and negative electrode materials and electrolyte, as well as battery design and construction. Lithium-rich manganese-based cathode materials with high discharge specific capacity (~300 mAh/g) are considered to be the ideal choice to achieve this technical goal, but their voltage decay, large first-time irreversible capacity, and poor cycle life are more prominent. . However, problems such as poor reversibility of electrochemical deposition/dissolution behavior of lithium metal anodes, easy dendrite growth, large volume changes during charge and discharge, and accumulation of "dead lithium" also need to be resolved urgently. For the electrolyte, it is necessary to match the needs of new positive and negative materials at the same time, and balance the relationship between the injection volume, viscosity and conductivity. In addition, the cell design, assembly process and test procedures of lithium metal secondary batteries cannot copy the traditional lithium ion battery process system, and a lot of process innovation is required. In the past five years, the Liu Zhaoping research team of Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences has conducted in-depth research on key materials and system construction of high-energy density lithium batteries, and has made a series of progress. Researchers have conducted research on key issues such as reducing the first irreversible capacity of lithium-rich manganese-based cathode materials, voltage attenuation and oxygen evolution during cycling, and have achieved a series of results (Nature Communications, 2016, 7, 12108; ACS Applied Materials & Interfaces, 2017 , 9, 3661; Advanced Material Interfaces, 2018, 1701465; ACS Applied Materials & Interfaces, 2019, 14, 14023; Energy Storage Materials, 2019, 16, 220; Cell Reports Physical Sciences, 2020, 1, 100028; Matter, 2021, 4, 1; Energy Storage Materials, 2021, 3, 388); focus on research and development of lithium-rich manganese-based cathode material engineering technology; according to actual battery requirements (high reversible area capacity, low N/P ratio, and low injection volume), Aiming at common problems such as serious volume expansion of metal lithium anode, unstable electrolyte/electrode interface, and short cycle life, innovative research on high capacity and long life metal lithium anode has been carried out. Through the composite reconstruction of graphene and metal lithium, the controllable load of metal lithium on graphene and the improvement of the stability of lithium deposition under high area capacity are realized, while the volume expansion during the cycle is reduced, and the "dead lithium" is alleviated. Mass transfer caused by layers (Advanced Energy Materials, 2018, 1703152; Energy Storage Materials, 2018, 15, 226; ACS Applied Materials & Interface, 2018, 10, 20387; Energy Storage Materials, 2019, 21, 107; Energy Storage Materials , 2019, 23, 693.); designed and constructed a series of stable electrolyte/electrode artificial interface layers, and deeply explored its mechanism of action (Nano Energy, 2019, 62: 55-63; Energy Storage Materials, 2019 , 23: 418-426; Journal of Materials Chemistry A, 2019, 7, 6267.). Researchers have also made progress in high-safety and high-voltage resistant electrolytes and their applications in lithium ion/lithium metal batteries (Electrochimica Acta, 2015, 151, 429; Journal of Power Sources, 2015, 278, 190; Journal of Power Sources, 2018, 391, 113-119; Electrochimica Acta, 2019, 320, 134633; Journal of Energy Chemistry, 2020, 48, 375–382.), in the design and manufacturing process of lithium metal secondary battery cells Carrying out technology research and development, applying for a series of invention patents, initially establishing the entire battery process technology, and formulating lithium metal secondary battery testing and evaluation procedures. In order to further achieve the long-life goal of lithium metal secondary batteries, researchers changed the lithium ion by adding highly fluorinated ether solvents to the conventional carbonate-based electrolyte (1.0 M LiPF6 in EC/DMC with 2 wt.% LiPO2F2) The solvation structure allows LiPO2F2 to be precipitated from the electrolyte in solid form and cover the surface of the positive and negative electrodes, which effectively enhances the high voltage tolerance of the electrolyte/positive electrode interface and improves the reversibility of the deposition behavior of the lithium negative electrode. Based on the research and development basis of key materials and battery cell technology for lithium metal secondary batteries, scientific researchers use lithium-rich manganese-based cathode materials as the positive electrode and lithium metal as the negative electrode. The new electrolyte system is designed to build a capacity of 3.6Ah and energy. A new type of lithium metal secondary battery with a density of 430Wh/kg and exhibits excellent cycle stability. Related research results were published on ACS Energy Letters. The research work has won the National Key R&D Program Project, National Natural Science Foundation Project, Chinese Academy of Sciences Strategic Leading Science and Technology Project, Chinese Academy of Sciences Science and Technology Service Network Plan (STS), Chinese Academy of Sciences International Partnership Program’s key foreign cooperation projects, Ningbo’s “Science and Technology Innovation 2025†major special project and Funding from the China Postdoctoral Science Foundation project. Foshan TianPuAn Building Materials Technology Co.,Ltd. , https://www.tpa-prefabhouse.com
430Wh/kg lithium metal secondary battery and its electrochemical performance