Mn_0.26V₂O₅·nH₂O Nanoribbons with Fast Ion Diffusion Channels and High Electrical Conductivity for Intercalation Pseudocapacitive Zn²⁺ Storage

Abstract

Zn 2+ intercalation pseudocapacitance is a desirable reaction mechanism to achieve high-energy and high-power-density aqueous zinc-ion batteries (AZIBs). However, engineering an intercalation pseudocapacitive cathode for AZIBs remains challenging owing to the sluggish Zn 2+ diffusion kinetics and low electrical conductivity of cathode materials. Here, a novel Mn 0.26 V 2 O 5 •nH 2 O nanoribbon cathode synthesized by a facile ionpreintercalated/-doped strategy is reported for intercalation pseudocapacitive Zn 2+ storage. The preintercalated Mn ions greatly increase the interlayer spacing of V 2 O 5 , providing enough space and active sites for Zn 2+ diffusion and accommodation. Meanwhile, the Mn doping-induced high electrical conductivity and water-lubricated channels promote both the electron transfer and Zn 2+ diffusion to guarantee the occurrence of intercalation pseudocapacitance. In addition, the nanoribbons have a small surface area of 11 m 2 g −1 due to the structural stacking, which reduces the surface capacitance and is able to shed light on the intercalation pseudocapacitive mechanism. The as-built cathode harvests a high capacity of 484 mA h g −1 at 0.1 A g −1 and an admirable capacity retention of 95% after 500 cycles, as well as an excellent rate capability of 212 mA h g −1 at 5.0 A g −1 . This proposed strategy has great implications in the design of intercalation pseudocapacitive materials for AZIBs and beyond.

Conductive coating, cation‐intercalation, and oxygen vacancies co‐modified vanadium oxides as high‐rate and stable cathodes for aqueous zinc‐ion batteries

“…Typical peaks located at 518, 766, and 1002 cm À1 assign to the interaction between V and O, the peaks at 933 cm À1 indicate the formation of Mn O bonds, while the visible peaks at 1620 cm À1 attribute to the O H vibration in the H 2 O molecules (Figure 2C). 37,38 These results confirm the formation of Mn 2+ -ions and H 2 O molecule co-inserted vanadium oxides. Notably, apart from the characteristic bands of MnVOH, there were some discriminative peaks in concert with the interaction between C, S, and O (e.g., the peaks at 1506 and 1407 cm À1 of C C and C C bonds, at 1247, 1156, and 1070 cm À1 of C O C bonds, as well as the peaks at 1116 cm À1 of C S bonds), suggesting the formation of PEDOT in MnVOH@PEDOT.…”

Amorphous MoO2/C Nanospheres–Porous Graphene Composites for Pseudocapacitive Li Storage

“…Figure b gives the b -values of peaks 1 and 2 (0.71 and 0.94, respectively), showing that MoO 2 /C-rGO is controlled by a hybrid mechanism of diffusion and capacitance. The k 1 – k 2 analysis was used to separate the capacitive and diffusion-controlled charges − at a scan rate of 1.5 mV s –1 , the capacitive charge reaches a very high ratio of 85.3% (Figure c). We also calculated the capacitive charge at other scan rates (Figure d) and found that the capacitance dominates the electrochemical reaction.…”

Foldable chromium vanadate cathodes for high-performance aqueous zinc ion batteries

“…S12 †), which means that some Zn 2+ ions are adsorbed on the surface. 54,55 In other words, some of the Zn 2+ ions are embedded in the interlayer, and some are adsorbed on the surface of the material.…”