2134/26303 Cheng Hu Cheng Hu Caroline Kirk Caroline Kirk Joaquin Silvestre-Albero Joaquin Silvestre-Albero Francisco Rodriguez-Reinoso Francisco Rodriguez-Reinoso Mark Biggs Mark Biggs Free-standing compact cathodes for high volumetric and gravimetric capacity Li-S batteries Loughborough University 2017 untagged Chemical Sciences not elsewhere classified 2017-08-31 16:13:26 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Free-standing_compact_cathodes_for_high_volumetric_and_gravimetric_capacity_Li-S_batteries/9390236 Free-standing high performance Li-S battery cathodes are currently attracting significant research efforts. Loose macroporous structures have been proposed by many to improve sulfur utilization and areal capacity. However, their low cathode sulfur densities and high electrolyte fractions lead to low cell volumetric and gravimetric capacities. We report here a compact free-standing Li-S cathode structure that delivers areal, volumetric and gravimetric capacities all exceed those of typical Li-ion batteries. The cathodes, formed by pressure filtration of the constituents, are composed of highly micro/mesoporous nitrogen-doped carbon nanospheres (NCNSs) embedded in the macropores of a multi-walled carbon nanotube (MWCNT) network to form a dense structure. The MWCNT network facilitates low cathode impedance. The NCNSs maximize sulfur utilization and immobilization. These collectively result in high cathode volumetric capacity (1106 mAh cm-3) and low electrolyte requirement (6 µL mg-1 of sulfur), which together leads to high cell-level gravimetric capacity. Stable long-term cycling at 0.3 C (2.5 mA cm-2 for 5 mg cm-2 areal sulfur-loading) has also been achieved, with the areal and volumetric capacities of the best remaining above typical Li-ion values over 270 cycles and the per-cycle capacity fading being only 0.1%. The facile preparation means significant potential for large scale use.