Engineering of three-dimensional nanohybrids: Co9S8 nanocrystal coated hollow carbon nanosphere for advanced lithium storage

Flower-like Mn/Co Glycerolate-Derived α-MnS/Co9S8/Carbon Heterostructures for High-Performance Lithium-Ion Batteries

“…Figure a shows the CV curves of MCS/carbon at 0.2 mV s –1 between 0.01 and 3.0 V. Distinctly, there are four peaks at 0.48, 0.98, 1.28, and 1.65 V in the first cathodic sweep. The weak peak at 1.65 V and the strong peak at 0.98 V are correspondingly related with the lithium insertion of Co 9 S 8 (Co 9 S 8 + x Li + → Li x Co 9 S 8 ) and the further reduction of Co 9 S 8 to mental Co (Co 9 S 8 + 16Li + + 16e – → 8Li 2 S +9Co). , Beside, the other two peaks at 1.28 and 0.48 V are explained as the lithium insertion of the α-MnS (MnS + 2Li + → Li 2 MnS) and the following conversion into metallic Mn (Li 2 MnS + 2e – → Mn + Li 2 S) . In the following cathodic scans, the reduction peak at 0.98 V still exists but moves higher to 1.29 V, while the peak at 0.48 V turns into two peaks at 0.40 and 0.69 V because of the irreversible structural changes during the activation process. , Correspondingly, three anodic peaks at 1.32, 2.10, and 2.35 V are because of the reversible oxidation of the metallic Mn/Co to sulfide. ,, The subsequent CV graphs are almost coincident, meaning high reversibility of the electrochemical reaction in MCS/carbon.…”

“…The weak peak at 1.65 V and the strong peak at 0.98 V are correspondingly related with the lithium insertion of Co 9 S 8 (Co 9 S 8 + xLi + → Li x Co 9 S 8 ) and the further reduction of Co 9 S 8 to mental Co (Co 9 S 8 + 16Li + + 16e − → 8Li 2 S +9Co). 11,43 Beside, the other two peaks at 1.28 and 0.48 V are explained as the lithium insertion of the α-MnS (MnS + 2Li + → Li 2 MnS) and the following conversion into metallic Mn (Li 2 MnS + 2e − → Mn + Li 2 S). 44 In the following cathodic scans, the reduction peak at 0.98 V still exists but moves higher to 1.29 V, while the peak at 0.48 V turns into two peaks at 0.40 and 0.69 V because of the irreversible structural changes during the activation process.…”

“…8,9 Especially, compared with TM oxides, the TM sulfides (TMSs) possess more abundant redox reactions, higher electrochemical activities, and a more suitable discharging−charging platform, which shows great potential for high-performance lithium storage applications. 10,11 However, TMSs are often subjected to poor electrical conductivity and a serious pulverization problem because of the bad structural stability during the cycling lithiation/delithiation processes, thus resulting in unsatisfactory cycling stability. 12 To address the above problems, various solutions are proposed, like nanostructuring and carbon hybridization.…”

“…More importantly, the rich valence states of the TM elements endow their compounds ( e.g. , sulfides or oxides) with easy electron transfer through conversion reactions. , Especially, compared with TM oxides, the TM sulfides (TMSs) possess more abundant redox reactions, higher electrochemical activities, and a more suitable discharging–charging platform, which shows great potential for high-performance lithium storage applications. , However, TMSs are often subjected to poor electrical conductivity and a serious pulverization problem because of the bad structural stability during the cycling lithiation/delithiation processes, thus resulting in unsatisfactory cycling stability …”

Customized Structure Design and Functional Mechanism Analysis of Carbon Spheres for Advanced Lithium–Sulfur Batteries

“…[302] FeS was acted as electrocatalytic active site to promote the conversions of intermediate LiPSs. In addition, the hollow N-doped CSs decorated with nanosized SnS 2 , [12] Co 9 S 8 nanocrystal-coated hollow carbon nanospheres, [306] and yolkshell NiS 2 /CSs [304] have recently been designed and synthesized to further catalyze the LiPSs transformation. The modification of SnS 2 on NHCS can activate the carbon-SnS 2 -electrolyte triple phase catalytic effect of LiPSs conversion in electrolyte and facilitate the uniform deposition of solid Li 2 S on the Figure 14.…”