For the practical use of high-capacity silicon anodes in high-energy lithium-based batteries, key issues arising from the large volume change of silicon during cycling must be addressed by the facile structural design of silicon. Herein, we discuss the zeolite-templated magnesiothermic reduction synthesis of mesoporous silicon (mpSi) (mpSi-Y, -B, and -Z derived from commercial zeolite Y, Beta, and ZSM-5, respectively) microparticles having large pore volume (0.4-0.5 cm/g), wide open pore size (19-31 nm), and small primary silicon particles (20-35 nm). With these appealing mpSi particle structural features, a series of mpSi/C composites exhibit outstanding performance including excellent cycling stabilities for 500 cycles, high specific and volumetric capacities (1100-1700 mAh g and 640-1000 mAh cm at 100 mA g), high Coulombic efficiencies (approximately 100%), and remarkable rate capabilities, whereas conventional silicon nanoparticles (SiNP)/C demonstrate limited cycle life. These enhanced electrochemical responses of mpSi/C composites are further manifested by low impedance build-up, high Li ion diffusion rate, and small electrode thickness changes after cycling compared with those of SiNP/C composite. In addition to the outstanding electrochemical properties, the low-cost materials and high-yield processing make the mpSi/C composites attractive candidates for high-performance and high-energy Li-ion battery anodes.

A new sulfur-loading method for S/mesoporous carbon cathodes coupled with a new type of carbon-coated separator is successfully demonstrated to enhance Li–S battery performances.

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Discrete hollow carbon spheres (HCSs) with a high surface-to-volume ratio and distinct conducting shell have attracted immense attention as electrode materials for batteries and supercapacitors. In this study, we developed a novel and scalable method to synthesize well-defined HCSs. The HCSs were prepared using a pyrolytic soft template of styrene/acrylic acid copolymer microspheres. Sulfur could be effectively confined inside the pores of the uniform-sized HCSs (average diameter = 320 nm, shell thickness = 40-50 nm) to produce a S/HCS-65-IM (S content = 65 wt%) Li-S cathode using a modified sulfur-loading method involving solution impregnation followed by melt-diffusion (IM). S/HCS-65-IM delivered much higher capacity and greater cycling stability over 200 cycles and showed much lower impedance build up than S/HCS-65-PM prepared via the conventional melt-diffusion of a physical mixture of sulfur powder and HCSs. The sulfur utilization of S/HCS-65-IM was further improved by more than 20% by suppressing its lithium-polysulfide shuttle effect using a carbon-coated separator (CCS). The S/HCS-65-IM cathode (with CCS) also exhibited excellent cycling stability (capacity retention of >81% after 200 cycles at 0.5 C) and high rate capability with a reduced interfacial charge transfer resistance, suggesting that S/HCS-65-IM (with CCS) is a promising cathode for Li-S batteries.

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