With the progress of science and technology, people put forward higher requirements on the energy density and safety performance of the battery.Because magnesium has the advantages of high volumetric capacity, negative growth of dendrites, abundant earth reserves and low cost, low cost However, the development of magnesium secondary batteries has been limited by the lack of electrolyte and cathode materials. Cheap and readily available sulfur as a widely studied cathode material for the conversion of batteries, magnesium The development of secondary battery cathode material brings hope.The magnesium / sulfur battery system using magnesium as anode and sulfur as cathode has a theoretical energy density of up to 1722Wh / kg, which is four times that of commercial lithium cobalt oxide / graphite battery system Very high potential for energy-saving low-cost energy storage battery system.
Recently, relying on Qingdao Institute of Bioenergy and Process Technology, Chinese Academy of Sciences Institute of Energy Storage and Storage Technology (hereinafter referred to as 'Qingdao Energy Storage Institute'), on the basis of previous work on magnesium secondary batteries, through one-step synthesis in situ , Obtained a new magnesium borate electrolyte, which effectively improves the cycle performance and rate performance of the magnesium / sulfur battery. It is expected to put the low cost and high energy density magnesium / sulfur battery system into practical use, and the related research results are published In Energy & Environment Science magazine.
In this study, THPB, MgCl 2 and Mg powder were used as raw materials to obtain the product B '(B) in one-step in-situ reaction in DME solvent. HFP) 4'-anions, and Mg4Cl6 (DME) 6'2 + as a cation-based organoboronic acid-based electrolyte.The electrolyte system exhibits excellent Mg ion conductivity: the electrochemical window is up to 3.3V (vs. Mg ), The ionic conductivity is as high as 5.58 mS / cm, the potential for electrodeposition is only 0.11 V, the coulombic efficiency for depositing dissolved magnesium is more than 98%, and the electrolyte has excellent non-nucleophilic property and is well compatible with sulfur positive electrode. The magnesium / sulfur battery assembled with the electrolyte still has a discharge specific capacity of 1000 mAh / g after 100 cycles of charging and discharging, and is still able to work normally under a high-current charge-discharge condition of 500 mA / g, which is currently reported Magnesium sulfur battery research in the most excellent performance data.
The simple synthesis method and the excellent performance of magnesium sulfur battery are the biggest advantages of the organo magnesium borate based electrolyte and the research results are expected to accelerate the practical progress of the magnesium / sulfur battery system.The research has obtained the National Outstanding Youth Fund, Qingdao Energy Reserve Fund and Qingdao Energy '135' project support.
