Ultralong-life and high-capacity magnesium/sodium hybrid-ion battery using a ternary CoSe/NiSe2/CuSe2 cathode and dual-ion electrolyte.

Abstract

An ultrahigh-performance magnesium/sodium hybrid-ion battery (MNHB) is developed using ternary CoSe/NiSe2/CuSe2 (CNCS) "micro-flowers" as cathode materials, working with a coordinative [Mg2Cl2][AlCl4]2 and bis(trifluoroethylsulfonyl)imide anionic sodium salt in triglyme electrolyte. After 2000 cycles at 2.0 A g-1, the MNHB shows a stable capacity of 115.5 mA h g-1 and a high Coulombic efficiency exceeding 99.8%. The battery shows very rapid charging, and good stability in extreme environments, providing new opportunities to develop other hybrid-ion systems.