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The sluggish kinetics of the sulfur conversion reactions in Li–S batteries is a critical challenge for their application. Thus, many studies have been dedicated to promoting the conversion process by including either functionalized matrix materials in the cathode or redox mediators in the electrolyte. Herein, by embedding a solid auxiliary redox species, we designed and prepared a composite that can be used as a matrix for a sulfur cathode. Differing from the conventional method, in which all the so-called redox mediators utilized are dissolved in the electrolyte, we employed a solid auxiliary redox species, a cobalt phthalocyanine complex supported on graphene structures, as skeleton materials of sulfur to promote the conversion kinetics in Li–S batteries. The graphene–cobalt phthalocyanine hybrid played a prominent role in promoting the kinetics of polysulfide conversion with multiple functions of reducing the activation energy hill, transferring electrons, suppressing the shuttle effect, etc. Consequently, the Li–S battery with the graphene–cobalt phthalocyanine–sulfur cathode showed better electrochemical performance than the battery with the graphene–sulfur cathode. Typically, a high initial capacity of 1400 mA h g−1 was achieved at 0.1C during the initial activation cycle, and the 1st and 300th cycle capacities at 0.5C were 1116 and 860 mA h g−1, respectively. Additionally, at a rate of 0.3C, high capacities of 1182 and 869 mA h g−1 were obtained during the 1st and 500th cycles, respectively. Furthermore, enhanced rate capability was achieved, delivering a capacity of 874 mA h g−1 at a rate of 2C.

Developing highly active Pd-based nanocatalysts with a well-organized structure is desired for direct alcohol fuel cell commercialization. In this study, room temperature seed mediated growth strategy has been successfully developed to prepare ternary Pd@Cdx-Agy core-shell as advanced novel non-Pt anode nanocatalysts for ethanol oxidation reaction EOR in alkaline electrolyte. The introduction of oxophilic Cd and Ag metals into Pd nanocatalysts can reduce the adsorption energy of OHads on the Pd@Cdx-Agy nanocatalysts and inhibit the COads on the Pd surface. Morphological characterization demonstrates that the as-synthesized Pd@Cdx-Agy nanocatalysts are well-organized core-shell nanostructure with Pd NPs as the core and Cd-Ag alloy as the shell. Moreover, electrochemical results indicate that the Pd@Cd1-Ag1 core-shell catalyst exhibit a remarkable electrochemical activity ( 2995.76 mA mg Pd − 1 ), excellent CO tolerance and long-term durability compared to those of Pd@Cd ( 1285.9 mA mg Pd − 1 ), Pd@Ag ( 2423.52 mA mg Pd − 1 ) and commercial Pd/C (JM) ( 477.4 mA mg Pd − 1 ) nanocatalysts. The excellent catalytic activity and stability of Pd@Cd1-Ag1 nanocatalyst can be associated to their huge electrochemical active surface area, positive influence of Cd-Ag NPs on Pd NPs and the unique well-organized core-shell nanostructure. These results suggested that the as-synthesized Pd@Cdx-Agy core-shell could serve as advanced catalysts towards alkaline DEFCs.