Lithium Magnesium Double Salt Electrolyte Activated, Nanostructured Rose Benzonate-Based Large Capacity Organic Magnesium Battery
The application of large-scale energy storage devices represented by smart grids places higher requirements on the cycle life, power density, cost, and safety of energy storage cells. The secondary magnesium-based battery at room temperature is a type of metal magnesium used as a negative electrode. The electrochemical energy storage system has rich negative earth crust reserves, low cost (the price of magnesium metal is less than 5% of the metal lithium price), large volumetric capacity (3833 mAh/cm3), no dendrite generation during electrochemical cycling, etc. Advantages, and the theoretical reduction potential of magnesium ions is only about 0.6V higher than that of lithium ions. As long as a suitable positive electrode structure framework is adopted, the magnesium-based battery can still maintain the energy density equivalent to that of the lithium ion battery. Moreover, the stable magnesium ions can be reversed. Deposition/stripping helps to suppress the volume expansion at the negative electrode end, reduces the electrolyte consumption, and significantly improves the cycle life and power density of the Mg-based battery. Therefore, the magnesium-based battery can satisfy the next-generation energy storage system without sacrificing the energy density. The indicator requirements.
However, the disadvantages of slow migration of magnesium ions within the lattice and the low theoretical capacity of inorganic frameworks still limit the widespread use of magnesium batteries. Lithium magnesium double salt electrolyte system is embedded in the positive lattice by the dominant lithium ions (instead of magnesium ions) The activation of positive and negative dynamics is achieved without sacrificing the stability of the cycling process of the magnesium metal negative electrode end, avoiding the disadvantages of the poor kinetic performance of magnesium ions, and greatly expanding the range of choice for the cathode material of magnesium batteries. Recently, Chinese Academy of Sciences Shanghai The team led by Li Chilin, a researcher at the Institute of Portland Research Institute, proposed a dual-salt electrolyte-activated multi-electron-reactive organomagnesium cell whose anode is made of green, renewable rosellite (such as Na2C6O6). Related results were published in the American Chemical Society. Publication ACS Nano (DOI: 10.1021/acsnano.7b09177).
Nanostructured organic systems with high density of carbonyl groups (C=O) as redox sites can achieve up to 350-400 mAh/g of reversible capacity (three-electron transfer), which can be further reduced by reducing graphene oxide (RGO) wiring High-rate electrochemical performance is achieved at 2.5 A/g (5 C) and 5 A/g (10 C) current densities of 200 and 175 mAh/g, respectively, and high rate performance also benefits from Under high current and long cycle conditions, the magnesium negative electrode still has no dendrite formation. This excellent performance benefits from the high intrinsic diffusion coefficient of lithium in Na2C6O6 (10-12-10-11cm2/s) and the contribution of tantalum capacitors greater than 60%. The strong non-lithium pinning effect (through Na-OC and Mg-OC) suppresses the flaking of the C6O6 layer in the crystal grains and achieves at least 600 charge and discharge cycles. The energy of the positive electrode active material of this organic magnesium battery Density can exceed 500 Wh/kg, can tolerate more than 4000 W/kg power density, this performance exceeds the level of high potential embedded cathode material based on inorganic structure.
The team has long been dedicated to the study of kinetics improvement strategies for magnesium-based batteries. An anion intercalation activation has been developed in the early stage. The magnesium fluorinated graphene battery exposed at the reaction center (Adv. Funct. Mater. 2015, 25, 6519–6526) was developed. A dual-salt magnesium-based battery based on a large-capacity polysulfide conversion reaction (AdvFunct Mater. 2015, 25, 7300-7308) was proposed to achieve a large-scale, long-cycle Mg-S battery approach (Adv Mater. 2018, 30, 1704166)
The research work has received funding and support from the National Key R&D Program, the National Natural Science Foundation of China, the Chinese Academy of Sciences 100-person Plan and the Shanghai Qianren Project.
