Ultrathin Nanoribbons of in Situ Carbon-Coated V₃O₇·H₂O for High-Energy and Long-Life Li-Ion Batteries: Synthesis, Electrochemical Performance, and Charge–Discharge Behavior

Abstract

The ever-growing demands of Li-ion batteries (LIBs) for high-energy and long-life applications, such as electrical vehicles, have prompted great research interest. Herein, by applying an interesting one-step high-temperature mixing method under hydrothermal conditions, ultrathin VO·HO@C nanoribbons with good crystallinity and robust configuration are in situ synthesized as promising cathode materials of high-energy, high-power, and long-life LIBs. Their capacity is up to 319 mA h/g at a current density of 100 mA/g. Moreover, the capacity of 262 mA h/g can be delivered at 500 mA/g, and 94% of capacity can be retained after 100 cycles. Even at a large current density of 3000 mA/g, they can still deliver a high capacity of 165 mA h/g, and 119% of the initial capacity can be kept after 600 cycles. Importantly, their energy density is up to 800 Wh/kg, which is 48-60% higher than those of conventional cathode materials (such as LiCoO, LiMnO, and LiFePO), and they can maintain an energy density of 355 Wh/kg at a high power density of 8000 W/kg. Furthermore, based on ex situ X-ray diffraction and X-ray photoelectron spectroscopy technology, their exact charge-discharge behavior is reasonably described for the first time. Excitingly, it is found for the first time that the as-synthesized VO·HO@C nanoribbons are also great promising cathode materials for Na-ion batteries.

Recent Progress in the Applications of Vanadium‐Based Oxides on Energy Storage: from Low‐Dimensional Nanomaterials Synthesis to 3D Micro/Nano‐Structures and Free‐Standing Electrodes Fabrication

“…However, it should be noted that although the cycling performance was improved, the capacity was decreased. In our recent work, [31] to further improve the cycling performance of V 3 O 7 ·H 2 O, a in situ carbon coating method was proposed to synthesize the ultrathin V 3 O 7 ·H 2 O@C nanoribbons based on HTMM for just 1 h. As-prepared V 3 O 7 ·H 2 O@C nanoribbons exhibited the improved electrochemical performance: the capacity was up to 319 mA h g −1 at 100 mA g −1 , a capacity of 262 mA h g −1 can be delivered at 500 mA g −1 with a capacity retention of 94% after 100 cycles, and especially their energy density was up to 800 W h kg −1 . Figure 2c, the crystal structures of V 3 O 7 ·H 2 O are basically analogous in terms of the edge-sharing VO 6 octahedral units forming zigzag chains, which are connected by the chains of edge-sharing VO 5 trigonal bi-pyramids by vertex sharing, then the joint chains of VO 6 -VO 5 build a V 3 O 8 layer.…”

“…Among various vanadium-based oxides, V 2 O 5 have attracted the most attention. [46] (326, 80% after 100 at 500) steel-supported V 6 O 13 [75] (≈300, ≈83 after 100 at 500) [31] (319, 94% after 100 at 500) NA NA VO 2 (B) VO 2 (B)@C nanosheets [76] (160, 78% after 50 at 100) VO 2 (B)@C-SLMBs [44] (206, 104% after 1000 at 1000) GVG [77] (421, 94% after 1500 at 18000) [78] (171, 48% after 60 at ≈50) box-in-box V 2 O 3 /C [79] (794, 116% after 1200 at 1000) NA [81,82] During discharging from 4.0 to 3.4 V: 0.…”

“…The interlayer-expanded V 6 O 13 nanosheets were synthesized to improve the cycling performance. [30,31,[125][126][127][128][129] For example, a PEO/V 3 O 7 ·H 2 O nanobelts composite was synthesized by hydrothermal method for 48 h. [129] The initial capacity of this kind of composite was 297 mA h g −1 , but the capacity decreased rapidly to ≈170 mA h g −1 after 40 cycles, and the capacity retention was 58%. It can also deliver a stable capacity when fabricated as a full cell.…”

“…These have been a lot of applications of vanadium-based oxides on electrode materials of LIBs and NIBs. [30,31] It was found that Li 3 VO 4 was a promising insertion anode material for LIBs with a low and safe discharge voltage (≈0.75 V vs Li/Li + in average), and delivered a large capacity (≈323 mA h g −1 ). [28] As cathode materials of NIBs, single-crystalline bilayered V 2 O 5 nanobelts can deliver a high capacity of 229 mA h g −1 at 80 mA g −1 .…”

Electrochromic Battery Displays with Energy Retrieval Functions Using Solution‐Processable Colloidal Vanadium Oxide Nanoparticles

“…[37] During the coloration process (0.2 V), the high valence state V 5+ was partially reduced to V 4+ and the atomic ratio of V 5+ /V 4+ decreased to 0.32 (Table S1, Supporting Information). [37] During the coloration process (0.2 V), the high valence state V 5+ was partially reduced to V 4+ and the atomic ratio of V 5+ /V 4+ decreased to 0.32 (Table S1, Supporting Information).…”