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    Fabrication of a Stable and Highly Effective Anode Material for Li-Ion/Na-Ion Batteries Utilizing ZIF-12
    (Wiley-V C H Verlag Gmbh, 2024) Bugday, Nesrin; Wang, Haoji; Hong, Ningyun; Zhang, Baichao; Deng, Wentao; Zou, Guoqiang; Hou, Hongshuai
    Transition metal selenides (TMSs) are receiving considerable interest as improved anode materials for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs) due to their considerable theoretical capacity and excellent redox reversibility. Herein, ZIF-12 (zeolitic imidazolate framework) structure is used for the synthesis of Cu2Se/Co3Se4@NPC anode material by pyrolysis of ZIF-12/Se mixture. When Cu2Se/Co3Se4@NPC composite is utilized as an anode electrode material in LIB and SIB half cells, the material demonstrates excellent electrochemical performance and remarkable cycle stability with retaining high capacities. In LIB and SIB half cells, the Cu2Se/Co3Se4@NPC anode material shows the ultralong lifespan at 2000 mAg-1, retaining a capacity of 543 mAhg-1 after 750 cycles, and retaining a capacity of 251 mAhg-1 after 200 cycles at 100 mAg-1, respectively. The porous structure of the Cu2Se/Co3Se4@NPC anode material can not only effectively tolerate the volume expansion of the electrode during discharging and charging, but also facilitate the penetration of electrolyte and efficiently prevents the clustering of active particles. In situ X-ray difraction (XRD) analysis results reveal the high potential of Cu2Se/Co3Se4@NPC composite in building efficient LIBs and SIBs due to reversible conversion reactions of Cu2Se/Co3Se4@NPC for lithium-ion and sodium-ion storage. The Cu2Se/Co3Se4@NPC material, which is synthesized from Cu@ZIF-12, utilizes the advantages of Cu and Co metal complexes to facilitate the storage of lithium and sodium ions. Defect-rich N-doped amorphous carbon (NPC) improves electrical conductivity, and the Cu2Se/Co3Se4@NPC composite material demonstrates remarkable cycle stability while retaining high capacities in LIB and SIB half cells. image
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    Manipulating Local Chemistry and Coherent Structures for High-Rate and Long-Life Sodium-Ion Battery Cathodes
    (Amer Chemical Soc, 2024) Wang, Haoji; Chen, Hongyi; Mei, Yu; Gao, Jinqiang; Ni, Lianshan; Hong, Ningyun; Zhang, Baichao
    Layered sodium transition-metal (TM) oxides generally suffer from severe capacity decay and poor rate performance during cycling, especially at a high state of charge (SoC). Herein, an insight into failure mechanisms within high-voltage layered cathodes is unveiled, while a two-in-one tactic of charge localization and coherent structures is devised to improve structural integrity and Na+ transport kinetics, elucidated by density functional theory calculations. Elevated Jahn-Teller [Mn3+O6] concentration on the particle surface during sodiation, coupled with intense interlayer repulsion and adverse oxygen instability, leads to irreversible damage to the near-surface structure, as demonstrated by X-ray absorption spectroscopy and in situ characterization techniques. It is further validated that the structural skeleton is substantially strengthened through the electronic structure modulation surrounding oxygen. Furthermore, optimized Na+ diffusion is effectively attainable via regulating intergrown structures, successfully achieved by the Zn2+ inducer. Greatly, good redox reversibility with an initial Coulombic efficiency of 92.6%, impressive rate capability (86.5 mAh g(-1) with 70.4% retention at 10C), and enhanced cycling stability (71.6% retention after 300 cycles at 5C) are exhibited in the P2/O3 biphasic cathode. It is believed that a profound comprehension of layered oxides will herald fresh perspectives to develop high-voltage cathode materials for sodium-ion batteries.