Jing Yao,Meichun He,Pengju Li,Chao Zhu,Dongmei Zhang,Cunyuan Pei,Bing Sun,Shibing Ni
NaxV2O5 is one type of representative cathode material for Li-/Na-ion batteries owing to its relatively high potential vs. Li/Na. Herein, a novel NaxV2O5 anode was successfully designed and synthesized via a reversed strategy, i.e., tuning the Na content in the NaxV2O5 cathode. Orthorhombic α′-NaxV2O5 (x ≈ 0.67) is firstly demonstrated to be a new high-performance anode for lithium-ion batteries (LIBs). Benefiting from its layered structure and the reasonably intercalated Na+, the as-synthesized α′-NaxV2O5 displays a high reversible capacity (535.8 mA h g−1 at 0.2 A g−1), excellent rate capability and ultra-long cycle life (91.2% capacity retention after 10 000 cycles). Furthermore, the exceptional performance of the α′-NaxV2O5 anode is showcased in an all-vanadium-based full cell. Importantly, ex situ XRD and XPS demonstrated that LizNaxV2O5 is the main and stable active material during cycling, and the lithium-ion storage process is mainly determined by pseudocapacitive behavior. This work brings new insights into the field of vanadate-based anode materials for LIBs.
Most recently, aqueous zinc-ion batteries (AZIBs) are the research focus because of their low cost, high safety, and eco-friendliness. In this respect, flexible binder-free electrodes have been investigated by several studies to keep pace with the development of wearable electronics. However, the mass loading of active materials in these electrodes is usually below 2 mg cm −2 , considerably limiting the areal capacity. Herein, we report a paper electrode prepared via a facile vacuum filtration technique with a high mass loading of 5 mg cm −2 for the active material, namely, reduced graphene oxide (rGO)/δ-Na x V 2 O 5 ·nH 2 O nanocomposite . Thanks to the homogeneous distribution and synergistic effect of the active material, carbon nanotubes , and cellulose fibers, the electrode not only exhibits good mechanical property and high electrical conductivity but also displays impressive performances for AZIBs. It achieves an admirable areal specific capacity of 1.87 mAh cm −2 (corresponding to 374.9 mAh g −1 for the active material), substantially higher than that of other flexible binder-free electrodes for (hybrid) AZIBs. Meanwhile, this electrode also shows good rate capability and excellent long-term cyclability (with a capacity retention of 92% over 4000 cycles). This work opens new opportunities towards flexible free-standing electrodes.
Xiong Liu,Guobao Xu,Shouji Huang,Lun Li,Yuan Wang,Liwen Yang
Aqueous zinc ion batteries (ZIBs) have drawn attractive attention due to low cost and high safety. However, further development and application of the aqueous ZIBs depend on cathode materials with large capacity, high rate and cyclic performances as well as high areal capacity. Herein, free-standing composite (named as NVO⊂CNTs 6:4) of Na x V 2 O 5 •nH 2 O (NVO) nanobelts and carbon nanotubes (CNTs) is fabricated by hydrothermal self-assembly followed vacuum filtration and freeze-drying processes. In virtue of porous and conductive architecture, the free-standing NVO⊂CNTs 6:4 composite exhibits good proton and Zn 2+ storage performance. When it is used as a cathode for the aqueous ZIBs, the battery exhibits large areal capacity of 3.03 mAhcm −2 at 3 mAcm −2 and superior high-rate capability of 210.4 mAhg −1 at 30 Ag −1 as well as long-term durability with capacity retention of 92.5% after 2500 cycles. Even at a high mass loading of 12 mgcm −2 , the battery can still deliver large capacity of 330.5 mAhg −1 at 2 Ag −1 . Our results disclose the NVO-based free-standing composite with high areal capacity, excellent rate and cyclic performances, highlighting its great potential application in high-performance aqueous ZIBs.
危险品化学品经营许可证（带存储）