Electrochemically Engineering a Single-Crystal Nickel-Rich Layered Cathode

Nickel-rich layered electrode material has been attracting significant attention owing to its high specific capacity as a cathode for lithium-ion batteries. Generally, the high-nickel ternary precursors obtained by traditional coprecipitation methods are micron-scale. In this work, the submicrometer single-crystal LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) cathode is efficiently prepared by electrochemically anodic oxidation followed by a molten-salt-assisted reaction without the need of extreme alkaline environments and complex processes. More importantly, when prepared under optimal voltage (10 V), single-crystal NCM exhibits a moderate particle size (∼250 nm) and strong metal-oxygen bonds due to reasonable and balanced crystal nucleation/growth rate, which are conducive to greatly enhancing the Li⁺ diffusion kinetics and structure stability. Given that a good discharge capacity of 205.7 mAh g^-1 at 0.1 C (1 C = 200 mAh g^-1) and a superior capacity retention of 87.7% after 180 cycles at 1 C are obtained based on the NCM electrode, this strategy is effective and flexible for developing a submicrometer single-crystal nickel-rich layered cathode. Besides, it can be adopted to elevate the performance and utilization of nickel-rich cathode materials.

Elemental Two-Dimensional Materials for Li/Na-Ion Battery Anode Applications

Two-dimensional (2D) nanostructure is currently the subject in the fields of new energy storage and devices. During the past years, a broad range of 2D materials represented by graphene have been developed and endow with excellent electrochemical properties. Among them, elemental 2D materials (Xenes) are an emerged material family for Li/Na-ion battery (LIB/SIB) anodes. Compared with other 2D materials and bulk materials, Xenes may exhibit some great superiorities for Li/Na storage, including excellent conductivity, fast ion diffusion and large active sites exposure. In this review, we provide a systematic summary of the recent progress and achievements of Xenes as well as their applications in LIBs/SIBs. The broad categorization of Xenes from group IIIA to VIA has been concisely outlined, and the related details in syntheses, structures and Li/Na-ion storage properties are reviewed. Further, the latest research progress of Xenes in Li/Na ion batteries are summarized, together with mechanism discussions. Finally, the challenges and prospects of Xenes applied to Li/Na ion battery are proposed based on its current developments.

Demystifying the Lattice Oxygen Redox in Layered Oxide Cathode Materials of Lithium-Ion Batteries

The practical application of lithium-ion batteries suffers from low energy density and the struggle to satisfy the ever-growing requirements of the energy-storage Internet. Therefore, developing next-generation electrode materials with high energy density is of the utmost significance. There are high expectations with respect to the development of lattice oxygen redox (LOR)-a promising strategy for developing cathode materials as it renders nearly a doubling of the specific capacity. However, challenges have been put forward toward the deep-seated origins of the LOR reaction and if its whole potential could be effectively realized in practical application. In the following Review, the intrinsic science that induces the LOR activity and crystal structure evolution are extensively discussed. Moreover, a variety of characterization techniques for investigating these behaviors are presented. Furthermore, we have highlighted the practical restrictions and outlined the probable approaches of Li-based layered oxide cathodes for improving such materials to meet the practical applications.