Nanostructured cathode materials with different dimensions (0D, 1D, 2D, and 3D), morphologies (hollow, core–shell, etc.), and composites (mainly graphene-based composites) are highlighted, aiming to unravel the opportunities for the development of future-generation lithium-ion batteries.

Layered Li-rich, Fe- and Mn-based cathode material, Li[Li0.2Fe0.1Ni0.15Mn0.55]O2, has been successfully synthesized by a coprecipitation method and further modified with different coating amounts of AlPO4 (3, 5, and 7 wt %). The effects of AlPO4 coating on the structure, morphology and electrochemical properties of these materials are investigated systematically. XRD results show that the pristine sample is obtained with typical Li-rich layered structure and trace amount of Li3PO4 phase are observed for the coated samples. The morphology observations reveal that all the samples show spherical particles (3-4 μm in diameter) with hierarchical structure, composed of nanoplates and nanoparticles. XPS analysis confirms the existence of AlPO4 and Li3PO4 phases at the surface. The electrochemical performance results indicate that the sample coated with 5 wt % AlPO4 exhibits the highest reversible capacity (220.4 mA h g(-1) after 50 cycles at 0.1C), best cycling performance (capacity retention of 74.4% after 50 cycles at 0.1C) and rate capability (175.3 mA h g(-1) at 1C, and 120.2 mA h g(-1) at 10C after 100 cycles) among all the samples. Cycle voltammograms show good reversibility of the coated samples. EIS analysis reveals that charge transfer resistance after coating is much lower than that of the pristine sample. The excellent electrochemical performances can be attributed to the effects of multifunctional AlPO4 coating layer, including the suppression of surface side reaction and oxygen vacancies diffusion, the acceleration of lithium ions transport as well as the lower electrochemical resistance. Our research provides a new insight of surface modification on low-cost Li-rich material to achieve high energy as the next-generation cathode of lithium-ion batteries.

Advanced lithium-ion batteries for renewable energy storage applications have become a major research interest in recent years. Much better performance can be realized by improvements in the material surface design, especially for the cathode materials. Here, we present a new design for a surface protective layer formed via a facile aqueous solution process in which a nanoarchitectured layer of LiF/FeF 3 is epitaxially grown on bulk hierarchical Li-rich cathode Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2. Coin cell tests of this material in the voltage range of 2-4.8 V indicated a high reversible capacity (260.1 mAh g-1 at 0.1C), superior rate performance (129.9 mAh g-1 at 20C), and excellent capacity retention. Differential scanning calorimetry showed good thermal stability. The enhanced capacity and cycling stability are attributed to the suppression of interfacial side reactions as well as the conversion reaction resulting from the introduction of LiF/FeF 3 as a surface protective layer.

As the most promising cathodes of lithium-ion batteries, lithium-rich manganese-based layered oxides with high capacity suffer from poor cycle stability, poor rate capability, and fast voltage fading. Here we introduced AlF3 into the surface of layered lithium-rich cathode (Li[Li0.2Fe0.1Ni0.15Mn0.55]O2) as an artificial protective layer as well as an inducer of integrated layered-spinel structures to achieve both low cost and high capacity. The reduced irreversible capacity loss, improved cycling stability, and superior high-rate capability were ascribed to the combination of AlF3 nanocoating and the unique structures as well as the low charge transfer resistance. Besides, the intractable issue, fast voltage fading of the layered lithium-rich cathode was also alleviated. Such materials with both low cost and high capacity are considered to be promising candidate cathodes to achieve lithium-ion batteries with high energy and high power.

Hierarchical mesoporous/macroporous ultrathin Co3O4 nanosheets were synthesized as free-standing catalysts for Li–O2 batteries. Morphology of Li2O2 could be changed by controlling the shape of catalysts..