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Double-shell SnO@C hollow nanospheres were synthesized by a template method, and then the sulfur was loaded to form a cathode material of S/SnO@C composite. In Li-S batteries, it delivered a high initial specific capacity of 1473.1 mAh/g at a current density of 200 mA/g, and the capacity retention was even up to 95.7% over 100 cycles at 3200 mA/g, i.e., a capacity fade rate of only 0.043% per cycle. These good electrochemical performances should be attributed to the SnO@C hollow nanospheres. They can enhance the electronic conductivity by the outside carbon shell, and confine the lithium polysulfides by S-Sn-O and S-C chemical bonds to suppress the shuttle effect. Besides, the hollow nanospheres can readily accommodate the sulfur/sulfides to prevent the electrical/mechanical failure of the cathode, instead of their agglomeration on the external surface of SnO@C.

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Layered LiNi0.8Co0.1Mn0.1O2 oxide (NCM811) has attracted wide attention as a candidate for the high-energy cathode in lithium-ion batteries (LIBs). It is necessary to amend both the insufficient cycling life caused by microstructural degradation and the poor rate capability due to the restricted kinetics, especially at high voltage. Here we design and synthesize a special NCM811 (R-NCM), containing primary particles arranged radially from the surface to the interior, to address these issues. Compared with the structure of primary particles randomly distributed in conventional NCM811 (C-NCM), this special microstructure in R-NCM shows more reversible cell volume variation, providing more open paths for Li+ transfer, and, more importantly, it significantly alleviates the mechanical stress induced by volume variation inside the particle when cycled to high voltage. Consequently, R-NCM delivers high reversible capacity (221.5 mAh g–1 at a current rate of 0.2 C) and increased rate capability (143 mAh g–1 at a current rate of 10 C) under a cutoff voltage of 4.6 V. Moreover, the long-term cycling stability in R-NCM at 4.6 V is remarkably increased due to the special microstructure. This morphological design provides a method for preparing advanced cathode materials for practical applications.

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A novel spatial confinement strategy based on a carbon/TiO /carbon sandwich structure is proposed to synthesize TiC nanoparticles anchored on hollow carbon nanospheres (TiC@C) through a carbothermal reduction reaction. During the synthesis process, two carbon layers not only serve as reductant to convert TiO into TiC nanoparticles, but also create a spatial confinement to suppress the aggregation of TiO , resulting in the formation of well-dispersed TiC nanoparticles. This unique TiC@C structure shows an outstanding long-term cycling stability at high rates owing to the strong physical and chemical adsorption of lithium polysulfides (i.e., a high capacity of 732.6 mA h g at 1600 mA g ) and it retains a capacity of 443.2 mA h g after 1000 cycles, corresponding to a decay rate of only 0.0395 % per cycle. Therefore, this unique TiC@C composite could be considered as an important candidate for the cathode material in Li-S batteries.