Self-assembled α-MnO2 urchin-like microspheres as a high-performance cathode for aqueous Zn-ion batteries

Abstract

Aqueous Zn-ion batteries (AZIBs) are one of the promising battery technologies for the green energy storage and electric vehicles. As one attractive cathode material for AZIBs, α-MnO 2 materials exhibit superior electrochemical properties. However, their long-term reversibility is still in great suspense. Considering the decisive effect of the structure and morphology on the α-MnO 2 materials, hierarchical α-MnO 2 materials would be promising to improve the cycle performance of AZIB. Here, we synthesized the α-MnO 2 urchin-like microspheres (AUM) via a self-assembled method. The porous microspheres composed of one-dimensional α-MnO 2 nanofibers with high crystallinity, which improved the surface area and active sites for Zn 2+ intercalation. The AUMbased AZIB realized a high initial capacity of 308.0 mA h g −1 , and the highest energy density was 396.7 W h kg −1 . The kinetics investigation confirmed the high capacitive contribution and fast ion diffusion of the AUM. Ex-situ XRD measurement further verified the synergistic insertion/extraction of H + and Zn 2+ ions during the charge/discharge process. The superiority of the AUM guaranteed good electrochemical performance and reversible phase evolution, and this application would promote the follow-up research on the advanced AZIB.

Boosting the Electrochemical Performance of V2O3 by Anchoring on Carbon Nanotube Microspheres with Macrovoids for Ultrafast and Long‐Life Aqueous Zinc‐Ion Batteries

“…The Ragone plots corresponding to p‐V 2 O 3 ‐CNT microspheres in comparison with the recently published literatures are shown in Figure S15, Supporting Information. [ 54–57 ] p‐V 2 O 3 ‐CNT microspheres exhibited energy densities of 298 and 135 Wh h kg −1 at power densities of 75 and 31 982 W kg −1 , which proved that the CNT networks and macrovoids in the V 2 O 3 microspheres helped achieve high energy density at ultrahigh power density. In the case of V 2 O 3 ‐CNT microspheres, the reversible capacities were similar to those of p‐V 2 O 3 ‐CNT microspheres at current densities equal to or lower than 10.0 A g −1 .…”

Recent Development of Mn‐based Oxides as Zinc‐Ion Battery Cathode

“…At current densities of 0.1 and 1 A g −1 , 308 and 170.2 mAh g −1 were obtained for its initial discharge capacity and retained specific capacity after 1000 cycles, respectively. The highest energy density of 396.7 Wh kg −1 was achieved with a power density of 129 W kg −1 [68] …”

Synthesis and Performance Optimization of Manganese‐based Cathode Materials for Zinc‐Ion Batteries

“…In addition, hydrothermal method has been widely used to synthesize nano-sized materials with various sizes and different morphologies. Figure 3(a-g) lists the different morphologies of MnO 2 , including nanoparticles, [58] nanowires, [59] nanorods, [60] nanofibers, [61] nanoflakes, [62] urchin-like microspheres with nanorods, [63] and nanospheres, [64] which were prepared through hydrothermal methods by changing the synthesis parameters (raw materials, temperature, time, etc.). First, these nano-sized and porous structures greatly provide sufficient active sites for energy storage.…”