Chemically Bonded Phosphorus/Graphene Hybrid As a High-Performance Anode for Lithium- and Sodium-Ion Batteries

Abstract

We report a red phosphorus-graphene nanosheet (P-G) hybrid as an anode material for lithium- and sodium-ion batteries. The hybrid was synthesized through a facile ball milling method where graphene stacks are exfoliated into graphene nanosheets and hybridized with red phosphorus particles during the process. The graphene nanosheets function as the conductive matrix in the hybrid and P-O-C chemical bonds are found between phosphorus and carbon in the hybrid, both of which facilitate creating robust and intimate contact between the graphene nanosheets and phosphorus and thus preventing loss of electrical contact by phosphorus particles during cycling. Benefiting from this structure, the P-G hybrid anode in lithium ion battery exhibits a high initial specific capacity of 2517 mAh/g at a current density of 130 mA/g and excellent cycling stability at ambient temperature. Moreover, even at elevated temperature of 60 oC, the hybrid anode delivers a high initial capacity of 2362 mAh/g at a current density of 260 mA/g and exhibits much better capacity retention of 74% after 200 cycles than conventional phosphorus-carbon additive hybrid. Also, the hybrid, used as anode for sodium-ion battery, delivers a high reversible capacity of 2077 mAh/g with excellent cycling stability (1700 mAh/g after 60 cycles) and high Coulombic efficiency (>98%). The attractive cycling stability at a wide range of temperature and its straightforward preparation approach of the new P-G hybrid make it a promising anode candidate for lithium- and sodium-ion batteries.We report a red phosphorus-graphene nanosheet (P-G) hybrid as an anode material for lithium- and sodium-ion batteries. The hybrid was synthesized through a facile ball milling method where graphene stacks are exfoliated into graphene nanosheets and hybridized with red phosphorus particles during the process. The graphene nanosheets function as the conductive matrix in the hybrid and P-O-C chemical bonds are found between phosphorus and carbon in the hybrid, both of which facilitate creating robust and intimate contact between the graphene nanosheets and phosphorus and thus preventing loss of electrical contact by phosphorus particles during lithiation/delithiation. Benefiting from this structure, the P-G hybrid anode in lithium ion battery exhibits a high initial specific capacity of 2517 mAh/g at a current density of 130 mA/g and excellent cycling stability at ambient temperature. Moreover, even at elevated temperature of 60 oC, the hybrid anode delivers a high initial capacity of 2362 mAh/g at a current density of 260 mA/g and exhibits much better capacity retention of 74% after 200 cycles than conventional phosphorus-carbon additive hybrid. Also, the hybrid, used as anode for sodium-ion battery, delivers a high reversible capacity of 2077 mAh/g with excellent cycling stability (1700 mAh/g after 60 cycles) and high Coulombic efficiency (>98%). The attractive cycling stability at a wide range of temperature and its straightforward preparation approach of the new P-G hybrid make it a promising anode candidate for lithium- and sodium-ion battery.