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Lithium-sulfur battery cathodes still remain a challenge on capacity decay due to the shuttle effect even though a series of strategies have been tried. Here we report a novel matryoshka-like CuS@void@Co 3 O 4 architecture of double micro-cubes (μ -cubes) that locks sulfur between the CuS core and the Co 3 O 4 shell. Plenty of existing spaces between the μ -cubes suffice a high loading of sulfur and volumetric accommodation. The robust, double closed cubes configuration greatly enhances the confinement of polysulfides. In parallel, the CuS core increases the electronic conductivity and contributes to additional capacity, while the Co 3 O 4 shell ensures a better interface activity. A high Li+ ion diffusion coefficient is obtained during the sulfur and lithium sulfide transformation. The constructed battery displays an initial capacity up to 1480 mAh g−1, and a Coulombic efficiency (CE) exceeding 99%. A capacity retention higher than 500 mAh g−1 with a CE larger than 99.8% after cycling 400 times at 0.2 C are achieved. In addition, under a temperature of −5 °C, a high capacity of 700 mAh g−1 at 0.2 C after 200 cycles is achieved, indicating a good low-temperature tolerance. [ABSTRACT FROM AUTHOR]

Cathode materials of Li-ion batteries are important for their overall Li-storage performance. However, current cathodes are still non-ideal with rapid capacity decay and poor stability. Herein, a composite cathode consisting of ternary LiMn 1/3 Co 1/3 Ni 1/3 O 2 particles anchored on reduced graphene oxide sheets is presented, which is prepared through a simple route. The composite cathode exhibits a stable capacity exceeding 120 mAh g−1 after 500 cycles at 0.2 C, along with a high Coulombic efficiency close to 100%, which are obviously improved compared to the pure LiMn 1/3 Co 1/3 Ni 1/3 O 2. In addition, the rate-performance of the composite is also significantly enhanced. We believe that the good electrochemical performance and the general preparation approach are able to enable the composite to find significant applications in high-performance secondary batteries. [ABSTRACT FROM AUTHOR]