High-performance magnesium/sodium hybrid ion battery based on sodium vanadate oxide for reversible storage of Na+ and Mg2+

Magnesium ion batteries (MIBs) are a potential field for the energy storage of the future but are restricted by insufficient rate capability and rapid capacity degradation. Magnesium -sodium hybrid ion batteries (MSHBs) are an effective way to address these problems. Here, we report a new type of MSHBs that use layered sodium vanadate ((Na, Mn)V 8 O 20 center dot 5H 2 O, Mn-NVO) cathodes coupled with an organic 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) anode in Mg 2+ /Na + hybrid electrolytes. During electrochemical cycling, Mg 2+ and Na + co -participate in the cathode reactions, and the introduction of Na + promotes the structural stability of the Mn-NVO cathode, as cleared by several ex -situ characterizations. Consequently, the Mn-NVO cathode presents great specific capacity (249.9 mA h g -1 at 300 mA g -1 ) and cycling (1500 cycles at 1500 mA g -1 ) in the Mg 2+ /Na + hybrid electrolytes. Besides, full battery displays long lifespan with 10,000 cycles at 1000 mA g -1 . The rate performance and cycling stability of MSHBs have been improved by an economical and scalable method, and the mechanism for these improvements is discussed. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.