RESUMEN
Vanadium nitride (VN) is a potential cathode material with high capacity and high energy density for aqueous zinc batteries (AZIBs). However, the slow kinetics resulting from the strong electrostatic interaction of the electrode materials with zinc ions is a major challenge for fast storage. Here, VN clusters with nitrogen-vacancy embedded in carbon (C) (Nv-VN/C-SS-2) are prepared for the first time to improve the slow reaction kinetics. The nitrogen vacancies can effectively accelerate the reaction kinetics, reduce the electrochemical polarization, and improve the performance. The density functional theory (DFT) calculations also prove that the rapid adsorption and desorption of zinc ions on Nv-VN/C-SS-2 can release more electrons to the delocalized electron cloud of the material, thus adding more active sites. The Nv-VN/C-SS-2 exhibits a specific capacity and outstanding cycle life. Meanwhile, the quasi-solid-state battery exhibits a high capacity of 186.5 mAh g-1, ultra-high energy density of 278.9 Wh kg-1, and a high power density of 2375.1 W kg-1 at 2.5 A g-1, showing excellent electrochemical performance. This work provides a meaningful reference value for improving the comprehensive electrochemical performance of VN through interface engineering.
RESUMEN
Initially, anode-free Li metal batteries present a promising power source that merges the high production feasibility of Li-ion batteries with the superb energy capabilities of Li-metal batteries. However, their application confronts formidable challenges of extremely short lifespan due to the inadequacy of zero-Li-excess cell configuration against irreversible Li loss. A Li compensation coupled interface engineering strategy is reported for realizing long-life quasi-solid-state anode-free batteries. The Li2 S is utilized as a sacrificial Li supplement to effectively counterbalance irreversible Li loss without damage to cell chemistry. Meanwhile, it demonstrates remarkable efficacy in establishing a robust yet slender inorganic-organic hybrid solid-state interphase for inhibiting cell degradation by dead and dendritic Li. This strategy enables quasi-solid-state anode-free batteries with a long lifespan of 500 cycles. The Ah-scale quasi-solid-state pouch cells, featuring a high-loading LiFePO4 cathode and lean gel polymer electrolyte, exhibit a high specific energy of 300 Wh kgcell -1 . This achievement translates into an improvement of 46% in gravimetric energy and 94% in volumetric energy compared to LiFePO4 ||graphite batteries while outperforming LiFePO4 ||Li-metal batteries by 22-47% in volumetric energy. Such quasi-solid-state anode-free cells also demonstrate good safety, showcasing remarkable resistance against nail penetration in ambient air without failure, smoke, or fire accidents.
RESUMEN
The development of intercalation anodes with high capacity is key to promote the progress of "rocking-chair" Zn-ion batteries (ZIBs). Here, layered BiOI is considered as a promising electrode in ZIBs due to its large interlayer distance (0.976 nm) and low Zn2+ diffusion barrier (0.57 eV) obtained by density functional theory, and a free-standing BiOI nanopaper is designed. The process and mechanism of Zn(H2O)n2+ insertion in BiOI are proved by ex situ X-ray diffraction, Raman, and X-ray photoelectron spectroscopy. The suitable potential (0.6 V vs Zn/Zn2+), high reversible capacity (253 mAh g-1), good rate performance (171 mAh g-1 at 10 A g-1), long cyclic life (113 mAh g-1 after 5000 cycles at 5 A g-1), and dendrite-free operation of BiOI nanopaper prove its potential as a superior anode. When it is coupled with Mn3O4 cathode, the quasi-solid-state battery exhibits a high initial capacity of 149 mAh g-1 (for anode) and a good capacity retention of 70 mAh g-1 after 400 cycles. The self-assembled flexible battery also shows stable charge-discharge during the cyclic test. This work shows the feasibility of BiOX anode for dendrite-free ZIBs.
RESUMEN
Rechargeable aqueous zinc-metal batteries (ZMBs) are considered as potential energy storage devices for stationary applications. Despite the significant developments in recent years, the performance of ZMBs is still limited due to the lack of advanced cathode materials delivering high capacity and long cycle life. In this work, we report a low-temperature and scalable synthesis method following a surfactant-assisted route for preparing manganese-doped hydrated vanadium oxide (MnHVO-30) and its application as the cathode material for ZMB. The as-prepared material possesses a porous architecture and expanded interlayer spacing. Therefore, the MnHVO-30 cathode offers fast and reversible insertion of Zn2+ ions during the charge/discharge process and delivers 341 mAh g-1 capacity at 0.1 A g-1. Moreover, the MnHVO-30||Zn cell retains 82% of its initial capacity over 1200 stability cycles, which is higher compared to that of the undoped system. Besides, a quasi-solid-state home-made pouch cell with an area of 3.3 × 1.6 cm2 and 3.6 mg cm-2 loading is assembled, achieving 115 mAh g-1 capacity over 100 stability cycles. Therefore, this work provides an easy and attractive way for preparing efficient cathode materials for aqueous ZMBs.
RESUMEN
High-Ni layered oxides are potential cathodes for high energy Li-ion batteries due to their large specific capacity advantage. However, the fast capacity fade by undesirable structural degradation in liquid electrolyte during long-term cycling is a stumbling block for the commercial application of high-Ni oxides. In this work, a functional gel polymer electrolyte, grafted with sodium alginate, is introduced to increase the stability of high-Ni oxide cathodes at the levels of both the particle and electrode. An in situ generated ion-conducting layer appears on the interface through the chemical interaction between transition-metal cations of the cathode and the metalophilic reticulum group in sodium alginate. Such a tailoring layer can not only enhance the interfacial compatibility on the cathode/electrolyte interface, reducing the interfacial resistance, but also inhibit the HF corrosion, suppressing the dissolution of transition-metal cations and harmful gradient distribution of components through the oxide cathode at the electrode level. Meanwhile, detrimental microcracks in oxide microspheres and between primary crystallites are impressively inhibited at the particle level. The high-Ni oxide cathode with the metalophilic gel polymer electrolyte shows excellent cycle stability with large initial capacity of 204.9 mA h g-1 at a 1.0 C rate and high discharge capacity retention within 300 cycles at high temperature.