Fast anion intercalation into graphite cathode enabling high-rate rechargeable zinc batteries

摘要

Cheap, high-rate and long-life batteries are urgently needed for grid-scale storage of renewable energy. Rechargeable zinc (Zn) batteries are potential candidates due to the high volumetric energy density and low cost of Zn anode. However, conventional Zn batteries employing metal oxide cathodes usually suffer from poor rate capabilities caused by the high migration barrier of Zn2+ in the metal oxide host structure. Here, we circumvent this dilemma by integrating Zn electrochemistry with bis(trifluoromethanesulfonyl) imide (TFSI-) anion (de) intercalation into graphite cathode based on a Zn(TFSI)(2)/acetonitrile electrolyte. Owing to the fast intercalation of TESI- along with the efficient Zn/Zn2+ redox kinetics, our Zn/graphite batteries enable an ultrafast charging rate up to 200C (to be fully charged in 18 s) and deliver a high power density of 16.3 kW kg(-1), which is comparable to those of supercapacitors. Besides, the rational utilization of the acetonitrile-based electrolyte further endows the resultant battery with dendrite-free Zn deposition, high voltage output (2.2 V) as well as wide-temperature adaptability from -40 to 80 degrees C, which is quite promising for grid-scale energy storage. Our work opens a new avenue for building high-rate low-cost batteries through coupling anion intercalation chemistry with multivalent metal anodes.