![]() ![]() However, this method inevitably leads to a series of problems such as high viscosity, high cost and poor dynamic behavior 17, 18, 19. Recently, “solvent-in-salt” has received wide attention, in fact by greatly increasing the concentration of the bulk electrolyte, forcibly reducing the content of the free solvent in the EDL to achieve the purpose of improving the electrochemical stability of overall electrolyte. Several methods have been employed to solve this problem. Ethers with a typical salts concentration of 1 M cannot be used with nickel-rich (such as LiNi 0.8Mn 0.1Co 0.1O 2, NMC811) or other high-voltage cathodes, therefore greatly hindered their application in high-energy density lithium metal batteries. Though with the above advantages, unfortunately, the poor oxidation stability (<4.0 V) greatly limits its application in high-voltage batteries. On the other hand, ethers exhibit several significant advantages compared with carbonates, such as excellent compatibility with lithium metal 12, superior Li + transport dynamics due to the extremely low viscosity 13, 14, and ultralow freezing point guarantee battery cycling at low temperatures 15, 16. On the one hand, carbonate electrolyte with high oxidation stability is highly corrosive to lithium metal, and porous SEI derived from carbonate solvent will lead to the continuous decomposition of solvent and the rapid failure of battery during lithium metal deposition and stripping 10, 11. Among the studies reported so far, carbonates and ethers are two most popularly employed solvents and show the best competitive comprehensive properties. Li/Li +) cathode materials face a dilemma 6, 7, 8, 9. Specifically, for lithium metal batteries, which is well-recognized as the next-generation energy storage devices, the development of suitable electrolytes for lithium metal batteries coupled with high-voltage (>4.0 V vs. These strategies are generally difficult to achieve a perfect balance among all the required performance of the energy storage system 3, 4, 5. However, for a long time, a great deal of research on electrolyte design in electrochemical devices has focused on the regulation of cation or anion solvation structure in bulk electrolyte, because the classical theory that bulk electrolyte structure determines EDL properties. The electric double layer (EDL) is the region where all electrochemical reactions occur, and its properties determine the process of the electrochemical reaction at the electrode/electrolyte interface 1, 2. This unconventional EDL structure breaks the inherent perception of the classical EDL rearrangement mechanism and greatly improve electrochemical performances of the device. Due to this design, the anodic decomposition of ether-based electrolytes is significantly suppressed in the high voltage cathodes and the battery shows outstanding performances such as super-fast charging/discharging and ultra-low temperature applications, which is extremely hard in conventional electrolyte design principle. It is enabled by adding functional anionic additives in the electrolyte, which can selectively bind with cations and free solvents, forming unique cation-rich and branch-chain like supramolecular polymer structures with high electrochemical stability in the EDL inner layer. In this work, we design a new EDL structure with adaptive and passivating properties. This promotes the continuous anodic decomposition of the electrolyte, leading to a limited operation voltage and cycle life of the devices. In electrochemical devices, such as batteries, traditional electric double layer (EDL) theory holds that cations in the cathode/electrolyte interface will be repelled during charging, leaving a large amount of free solvents. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |