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• NiCo 2 O 4 nanoparticles with different morphologies were prepared via template method and self-assembly method. • The NiCo 2 O 4 nanoparticles were in-situ decorated onto porous carbon (PC) and used as host of sulfur cathode for lithium sulfur battery. • The synergistic effect of physical binding of PC and adsorption catalysis of NiCo 2 O 4 nanoparticles could effectively improve the performance of lithium sulfur battery. Lithium-sulfur battery (LSB) is one of the most appealing candidates for advanced next-generation electrochemical energy storage systems based on the merits of extraordinary theoretical specific energy density, abundant resources and environmental friendliness of sulfur. However, the "shuttle effect" of lithium polysulfides (LiPSs) and low utilization of sulfur cathode severely plague the large-scale commercialization of the LSBs. In this work, a novel host material for sulfur cathode, namely porous carbon (PC) decorated with NiCo 2 O 4 nanoparticles (NiCo 2 O 4 /PC), was designed and prepared. Among all tested NiCo 2 O 4 nanoparticles with different morphologies, the NiCo 2 O 4 nanoparticles with honeycomb pore shape (C-NiCo 2 O 4) showed excellent performance as sulfur cathode host. Benefiting from the synergistic advantages between PC and C-NiCo 2 O 4 nanoparticles, the C-NiCo 2 O 4 /PC host materials showed strong adsorption for LiPSs, promising the alleviation of shuttle effect and promoting the catalytic conversion process of LiPSs. As a result, the LSBs with S@C-NiCo 2 O 4 /PC cathode delivered a high specific capacity of 1065.2 mAh g−1 at 0.1C, a stable cycling over 500 cycles with low fading rate of 0.053% per cycle at 0.5C and an enhanced rate capability compared with those of S@C-NiCo 2 O 4 and S@PC cathodes. This work demonstrated the synergistic effect of physical shackle from PC and adsorption-catalysis from NiCo 2 O 4 nanoparticles, which might provide new insights into the optimization of carbonaceous architecture for rationally regulating the polysulfide redox reactions. [ABSTRACT FROM AUTHOR]

• SbBi x nanoparticles embedded in ultra-thin carbon networks are designed. • SbBi x @C exhibits excellent performance in both sodium and potassium storage. • The influence of proportion in SbBi x on energy storage behavior is revealed. • SEI composition and particle surface states play an important role in energy storage. The alloy proportions of SbBi x show obvious influence on sodium/potassium storage. Herein, SbBi x nanoparticles embedded in ultra-thin carbon networks (SbBi x @C, x = 1, 0.5, 0.15) are successfully synthesized by a facile salt template assisted pyrolysis method. The effect of different alloy proportions on the chemical and electrochemical properties of active materials is revealed. Density functional theory calculation demonstrates that SbBi 0.5 has the smallest formation energy (−5.131 eV) and the smallest volume expansion rate for both sodium/potassium storage (222%/376%). Benefiting from the optimized volume expansion for both sodium/potassium storage and carbon networks structure, the optimized SbBi 0.5 @C anode shows high reversible capacities of 301 mAh/g and 390 mAh/g after 100 cycles at 0.1 A/g for sodium/potassium storage, respectively. It is also observed that the SbBi 0.5 @C anode delivers different behaviours of sodium/potassium storage, which is due to the various composition of SEI films formed after sodium/potassium storage. It is believed that this work provides a synthetic strategy for fabricating alloy-type anode materials for SIBs/PIBs, in view of structure design and the regulation of alloy proportion. [ABSTRACT FROM AUTHOR]