A High‐Volumetric‐Capacity Cathode Based on Interconnected Close‐Packed N‐Doped Porous Carbon Nanospheres for Long‐Life Lithium–Sulfur Batteries

Abstract

27Keywords: Li-S battery, high volumetric capacity, monodisperse, interconnected carbon 28 nanospheres, close-packed 29 30We report a Li-S battery cathode of high volumetric-capacity enabled by novel micro-and meso-31 structuring. The cathode is based on monodisperse highly porous carbon nanospheres derived from 32 a facile template-and surfactant-free method. At the mesoscale, the nanospheres structure into 33 interconnected close-packed clusters of a few microns in extent, thus facilitating the fabrication of 34 dense crack-free high areal sulfur loading (5 mg cm -2 ) cathodes with high electrical conductivity 35 and low cathode impedance. A combination of the nitrogen doping (5 wt%), high porosity (2.3 cm 3 36 g -1 ) and surface area (2900 m 2 g -1 ) at the microscale enables high sulfur immobilization and 37 utilization. The cathode delivers amongst the best reported volumetric capacity to date, above 38 typical Li-ion areal capacity at 0.2C over 200 cycles and low capacity fading of 0.1% per cycle at 39 0.5C over 500 cycles. The compact cathode structure also ensures a low electrolyte requirement (6 40 µL mg -1 ), which aids a low overall cell weight, and further, amongst the best gravimetric capacities 41 published to date as well. 42

Nanoengineering Carbon Spheres as Nanoreactors for Sustainable Energy Applications

“…g) Adsorption capability of N‐doped nanospheres in comparison with carbon black (Super P). e–g) Reproduced with permission . Copyright 2017, Wiley‐VCH.…”

Wrinkled Perovskite La0.9Mn0.6Ni0.4O3−δ Nanofibers as Highly Efficient Electrocatalyst for Rechargeable Li−O2 Batteries

“…The reversible formation and decomposition of Li 2 O 2 on the cathode is considered as the most primary factor to affect most of the aforementioned problems, deteriorating the performance of Li−O 2 battery. Aiming at the key factors, extensive researches have been devoted to developing various active catalysts, including carbon materials, precious metals or alloys, transition metal nitrides and oxides …”

“…The reversible formation and decomposition of Li 2 O 2 on the cathode is considered as the most primary factor to affect most of the aforementioned problems, deteriorating the performance of LiÀ O 2 battery. Aiming at the key factors, extensive researches have been devoted to developing various active catalysts, including carbon materials, [1][2][3] precious metals or alloys, [4][5][6] transition metal nitrides [7][8][9] and oxides. [10][11][12] As recently reported in the literatures, [13][14][15][16][17] perovskite oxides (ABO 3 ) have become attractive catalysts with prominent advantages of good ORR/OER activity, low cost, high electrochemical stability and relatively high ionic/electronic conductivity, which previously were widely applied in fuel cells.…”

Multifunctionality of Carbon-based Frameworks in Lithium Sulfur Batteries

“…The sulfur loading of cathodes in Li-S batteries must reach 4~6 mg cm −2 to compete with LIBs; therefore, high sulfur loading is required to meet practical application demands [13,128,129]. However, because of the insulating nature of sulfur, the high sulfur loading results in low rate capabilities and rapid capacity fading.…”

“…However, because of the insulating nature of sulfur, the high sulfur loading results in low rate capabilities and rapid capacity fading. To achieve high volumetric capacity, Hu et al [128] synthesized monodispersed porous nitrogen-doped carbon nanospheres (NCNSs) with a diameter about 350 nm using a template method. Here, the structure of the resulting carbon material was found to be interconnected with closely packed Fig.…”