In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melami...In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction（ORR） that was supe‐rior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half‐wave potential of –133.6 mV （vs. Ag/AgCl）, which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm^2, which is 0.2 mA/cm^2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4 e^– path. The above mentioned superiority of the as‐prepared catalyst makes it promising for fuel cells.展开更多
The rechargeable aluminum-sulfur(Al-S)battery is a promising alternative-energy storage device with high energy density and made of cheap raw materials.However,Al-S batteries face several obstacles,especially the shut...The rechargeable aluminum-sulfur(Al-S)battery is a promising alternative-energy storage device with high energy density and made of cheap raw materials.However,Al-S batteries face several obstacles,especially the shuttle effect.Herein,a binder-free S@Ti_(3)C_(2)T_(x)sandwich structure film with uniform sulfur dispersion was designed.The two-dimensional(2D)layered material Ti_(3)C_(2)T_(x) not only has the function of binder and conductive agent but also is a promising host for sulfur anchoring.As a result,S@Ti_(3)C_(2)T_(x)film showed an initial capacity of 489 mA h g^(−1)at 300 mA g^(−1) and retained the value at 415 mA h g^(−1)after 280 stable cycles,with an average Coulombic efficiency of~95%.The film displayed higher capacity and stability than the S+Ti_(3)C_(2)T_(x)cathode prepared by the slurry-coating method(the initial capacity was 317 mA h g^(−1)and then decayed to 222 mA h g^(−1) after 160 cycles).The main capacity of S@Ti_(3)C_(2)T_(x) film in the Al-S battery came from the reversible redox reaction of S^(2−) and S.This new 2D material combined with a controllable electrode structure design paves the way for the development of Al-S batteries.展开更多
文摘In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction（ORR） that was supe‐rior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half‐wave potential of –133.6 mV （vs. Ag/AgCl）, which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm^2, which is 0.2 mA/cm^2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4 e^– path. The above mentioned superiority of the as‐prepared catalyst makes it promising for fuel cells.
基金supported by the National Natural Science Foundation of China(51272155,21875061,21975066 and 21901157)the Open Research Fund Program of Science and Technology on Aerospace Chemical Power Laboratory(STACPL 120201B05)the National Key R&D Program of China(2021YFC2100100)。
文摘The rechargeable aluminum-sulfur(Al-S)battery is a promising alternative-energy storage device with high energy density and made of cheap raw materials.However,Al-S batteries face several obstacles,especially the shuttle effect.Herein,a binder-free S@Ti_(3)C_(2)T_(x)sandwich structure film with uniform sulfur dispersion was designed.The two-dimensional(2D)layered material Ti_(3)C_(2)T_(x) not only has the function of binder and conductive agent but also is a promising host for sulfur anchoring.As a result,S@Ti_(3)C_(2)T_(x)film showed an initial capacity of 489 mA h g^(−1)at 300 mA g^(−1) and retained the value at 415 mA h g^(−1)after 280 stable cycles,with an average Coulombic efficiency of~95%.The film displayed higher capacity and stability than the S+Ti_(3)C_(2)T_(x)cathode prepared by the slurry-coating method(the initial capacity was 317 mA h g^(−1)and then decayed to 222 mA h g^(−1) after 160 cycles).The main capacity of S@Ti_(3)C_(2)T_(x) film in the Al-S battery came from the reversible redox reaction of S^(2−) and S.This new 2D material combined with a controllable electrode structure design paves the way for the development of Al-S batteries.
