Nitrogen Doping Improves the Immobilization and Catalytic Effects of Co₉S₈ in Li‐S Batteries

Abstract

Several critical issues, such as the shuttling effect and the sluggish reaction kinetics, exist in the design of high‐performance lithium–sulfur (Li‐S) batteries. Here, it is reported that nitrogen doping can simultaneously and significantly improve both the immobilization and catalyzation effects of Co9S8 nanoparticles in Li‐S batteries. Combining the theoretical calculations with experimental investigations, it is revealed that nitrogen atoms can increase the binding energies between LiPSs and Co9S8, and as well as alleviate the sluggish kinetics of Li‐S chemistry in the Li2S6 cathode. The same effects are also observed when adding N‐Co9S8 nanoparticles into the commercial Li2S cathode (which has various intrinsic advantages, but unfortunately a high overpotential). A remarkable improvement in the battery performances in both cases is observed. The work brings heteroatom‐doped Co9S8 to the attention of designing high‐performance Li‐S batteries. A fundamental understanding of the inhibition of LiPSs shuttle and the catalytic effect of Li2S in the newly developed system may encourage more effort along this interesting direction.

Surface Engineering of 2D Carbon Nitride with Cobalt Sulfide Cocatalyst for Enhanced Photocatalytic Hydrogen Evolution

“…For the Co 2 p spectra of Co 9 S 8 , the peaks at 778.5 and 793.6 eV correspond to Co 3+ in Co 2 p 3/2 and Co 2 p 1/2 , respectively, and the peaks at 781.6 and 797.6 eV correspond to Co 2+ in Co 2 p 3/2 and Co 2 p 1/2 , respectively, in Figure 3c. [ 41,52,53 ] For the composite, a pair of new characteristic peaks appeared at 780.8 and 796.8 eV. The close results show that the characteristic peaks appear at 779.8 and 794.8 eV in the Co 2 p spectra of pure CoN (Figure S5a, Supporting Information).…”

Emerging Catalysts to Promote Kinetics of Lithium–Sulfur Batteries

“…As evidenced by the typical charge/discharge profiles within 1.6–2.8 V versus Li + /Li, the contributions of N‐Co 9 S 8 or Co 9 S 8 to the total capacity can be neglected. [ 96 ]…”

Defect Engineering for Expediting Li–S Chemistry: Strategies, Mechanisms, and Perspectives

“…[135,136] To further boost the capture of PS on Co 9 S 8 , Liu et al reported the synthesis of N-doped Co 9 S 8 nanoparticles (N-Co 9 S 8 ). [137] Figure 8a depicts the optimal adsorption configurations of PS intermediates on both (311) and (440) lattices of N-Co 9 S 8 and Co 9 S 8 , respectively. It is noted c) Reproduced with permission.…”

“…[139] Of note, the bond lengths of various sulfur species (Li c) Reproduced with permission. [137] Copyright 2020, Wiley-VCH. d) Potentiostatic discharge profiles of Li 2 S 8 /tetraglyme solution at 2.05 V. e) Dissociation barriers and pathways of Li 2 S cluster.…”

“…c) Adsorption ability test in the Li 2 S 6 solution. a-c) Reproduced with permission [137]. Copyright 2020, Wiley-VCH.…”