Organic salt-derived phosphorus-doped mesoporous carbon for high performance supercapacitors

Phosphorus-doped mesoporous carbons(PMCs)were prepared using a self-doping and self-templating approach via direct pyrolysis of sodium phytate(C_(6)H_(17)NaO_(24)P_(6)).The one-pot method allows simultaneous carbonization and P doping,eliminating the need for pre-synthesis or post-activation treatment.The C_(6)H_(17)NaO_(24)P_(6)is the source of both carbon and phosphorus,and the nano-Na_(4)P_(2)O_(7)particles produced during pyrolysis act as hard templates for the honeycomb mesoporous structure with high specific surface area(884–827m^(2)/g),large mesopore volume ratio(67%–75%)and rich phosphorus content(0.53–2.34 at%).As electrodes of supercapacitors in 6 mol/L KOH,the PMCs showed outstanding performance with a high capacitance of 202 F/g and excellent rate performance of 148 F/g at 30 A/g.In addition,the PMCs-based symmetrical supercapacitors can operate in an expanded working voltage of 0–1.6 V in 3mol/L H_(2)SO_(4)aqueous electrolytes with high-density energy of 11.8 Wh/kg.

Bi_(2)S_(3) nanorods encapsulated in iodine-doped graphene frameworks with enhanced potassium storage properties

Bismuth sulfide(Bi_(2)S_(3))is a promising anode material for high-performance potassium ion batteries due to its high theoretical capacity.However,the poor conductivity and substantial volume expansion hinder its practical application.We proposed an iodine-doped graphene encapsulated Bi_(2)S_(3)nanorods composite(Bi_(2)S_(3)/IG)as an efficient anode for PIBs.The uniform-sized Bi_(2)S_(3)nanorods evenly in-situ encapsulated in iodine-doped graphene framework,facilitating the electron transportation and structural stability.The potassium storage performance was evaluated in three electrolytes,with the best option of 5 mol/L KFSI in DME.The reversible capacity of representative Bi_(2)S_(3)/IG reached 453.5 m Ah/g at 50 m A/g.Meanwhile,it could deliver an initial reversible capacity of 413.6 m Ah/g at 100 m A/g,which maintained 256.9 m Ah/g after 200 cycles.The proposed strategy contributes to improving potassium storage performance of metal sulfide anodes.