A facile route to graphene-covered and carbon-encapsulated CoSO4 nanoparticles as anode materials for lithium-ion batteries.

Graphene-covered and carbon-encapsulated CoSO 4 nanoparticles (a-C@CoSO 4 @GNs) were first prepared by a facile solution-phase route followed by heat treatment. Subsequently, a-C@CoSO 4 @GNs nanoparticles were utilized as anode materials of Li ion batteries. Such a rationally designed three-dimensional nanostructure could effectively accommodate the volume expansion of CoSO 4 particles during Li-cycling. As a consequence, a-C@CoSO 4 @GNs have delivered remarkable electrochemical performances, i.e., high first discharge capacity (994 mA h g −1 ), prominent cyclic performance of 662.7 mA h g −1 at a current density of 200 mA g −1 and excellent large-current capacity of 497 mA h g −1 at a current density of 1.5 A g −1 after 50 cycles due to catalytically reduced mechanism. More importantly, a-C@CoSO 4 @GNs electrodes possessed outstanding low/high temperature properties, i.e., reversible capacity of 130 mA h g −1 at −20 °C and 1362 mA h g −1 at 60 °C at a current density of 200 mA g −1 . These advantageous attributes make inexpensive, easily available, widespread and non-toxic CoSO 4 promising candidate as anode materials for high-performance lithium-ion batteries under extremely operational environments. [ABSTRACT FROM AUTHOR]