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A series of xLiV3O8·yLi3V2(PO4)3/rGO (x : y = 2 : 1, 3 : 1, 1 : 1, 1 : 2, and 1 : 3) composites are synthesized by simple mechanical mixing of LiV3O8 and Li3V2(PO4)/rGO, which are prepared by the hydrothermal method and the sol–gel route, respectively. From scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs, the composites are found to be a mixture of rod-like LiV3O8 particles and flower-shaped Li3V2(PO4)/rGO. Among these composites, the 2LiV3O8·Li3V2(PO4)/rGO electrode delivers an initial discharge capacity of 197 mA h g−1 at a current density of 100 mA g−1 between 2.0 V and 4.3 V, and shows the best comprehensive electrochemical property. The diffusion coefficients of Li ions in the 2LiV3O8·Li3V2(PO4)/rGO electrode are in the range of 10−11.5 to 10−9.5 cm2 s−1 obtained using the galvanostatic intermittent titration technique (GITT).

A novel peanut-like hierarchical micro/nano-lithium-rich cathode material Li1.2Mn0.54Ni0.18Co0.08O2 has been successfully synthesized via a facile solvothermal method combined with a calcination process. XRD patterns show that the as-prepared sample has high crystallinity and a well-formed layered structure. As a cathode material for Li-ion batteries, this oxide exhibits high capacity, good cyclic stability and superior rate capability. It delivers a discharge capacity of 229.9 mA h g−1 at a current density of 200 mA g−1 between 2.0 and 4.8 V with a high capacity retention of 94.2% after 100 cycles. High reversible discharge capacities of 198.3, 167.5 and 145 mA h g−1 are obtained at 400, 1000 and 2000 mA g−1, respectively. This excellent electrochemical performance is attributed to the hierarchical micro/nanostructure.

Rational design and fabrication of advanced sulfur cathodes is highly desirable for the development of high performance lithium–sulfur (Li–S) batteries. Herein, we report Co(OH)2 as a new stabilizer for the sulfur cathode by constructing a cobalt hydroxide-covered sulfur/conductive carbon black (CCB) electrode with the help of thermal and hydrothermal treatments. In this composite, (Co(OH)2@S/CCB), the sublimed sulfur is anchored in the CCB, followed by a uniform coating of Co(OH)2 nanosheets. As cathode materials of lithium–sulfur batteries, the as-prepared Co(OH)2@S/CCB electrode exhibits remarkable electrochemical performances with a high capacity of 1026 mA h g−1 at 0.1C (1C = 1675 mA g−1) and 829 mA h g−1 at 1C. Moreover, it maintains high coulombic efficiencies above 97% after 200 cycles at 1C, much higher than those of the S/CCB counterpart electrode (85%). After 200 cycles at 1C, a high capacity retention of 71.2% is obtained, better than that of the S/CCB electrode (20.2%). The enhanced performance is mainly due to the Co(OH)2 layer which helps to inhibit the shuttle diffusion of polysulfides, resulting in improved capacity retention and cycling life.