Kinetics-Driven MnO₂ Nanoflowers Supported by Interconnected Porous Hollow Carbon Spheres for Zinc-Ion Batteries

Abstract

For rechargeable aqueous zinc-ion batteries (ZIBs), manganese dioxide is one of the most promising candidates as a cathode material because of its cost effectiveness, eco-friendliness, and high specific capacities. However, the ZIBs suffer from poor rate performance and low cycle life due to the weak intrinsic electronic conductivity of manganese dioxide, poor ion diffusion of lump manganese dioxide, and its volumetric expansion during the cycle. Herein, we prepare MnO 2 @carbon composites (MnO 2 @ IPHCSs) by in situ growing MnO 2 nanoflowers on an interconnected porous hollow carbon spheres (IPHCSs) template. IPHCSs, as excellent conductors, significantly improve the conductivity of the manganese dioxide cathode. The hollow porous carbon framework of IPHCSs can offer more ion diffusion paths to internal MnO 2 @IPHCS carbon composites and acts as a buffer room to cope with the drastic volume contraction and expansion during charge/discharge cycling. The rate performance tests show that MnO 2 @IPHCSs with high conductivity have a specific capacity of 147 mA h g −1 at 3 C. MnO 2 @IPHCSs with hollow and nanoflower structures are shown to have excellent ion diffusion performance (ion diffusion coefficient = 10 −11 to 10 −10 cm 2 s −1 ) in the electrochemical kinetics of the galvanostatic intermittent titration technique. Long cycle performance testing and in situ Raman characterization reveal that MnO 2 @IPHCSs have high cycling stability (85.5% capacity retention after 800 cycles) and reversibility due to the enhanced structure and increased conductivity. The excellently conductive manganese dioxide supported by IPHCSs has good rate and cycling performance, which can be used to produce superior-performance ZIBs.

Lignosulfonate-Assisted Synthesis of Porous Carbon-Supported MnO2 Composites with Reinforced Interface Bonding for High-Performance Asymmetric Supercapacitors

“…The Raman spectra in Figure b exhibit D peaks at 1345 cm –1 , which indicate defect structures, and G peaks at 1594 cm –1 , which suggest graphitized structures. − The I D / I G values for LSC and LSC/MnO 2 -2 are 0.98 and 1.0, respectively, indicating that KMnO 4 oxidation can increase the defect degree. Furthermore, LSC/MnO 2 -2 demonstrates stretching vibration modes associated with Mn–O bonds at 570 and 625 cm –1 , confirming the successful loading of MnO 2 onto the lignin carbon materials.…”

Low-Temperature and High-Performance Vanadium-Based Aqueous Zinc-Ion Batteries

“…have not been studied in a low-temperature environment. At the same time, because the ion transport rate is seriously slowed in the low-temperature system, for the cathodic material with a loose structure (such as MnO 2 ), after the cation is dissolved, it cannot return to the original lattice structure, which has an irreversible effect on the capacity. , Therefore, it is attractive and challenging to design a low-temperature and high-performance vanadate-based AZIB system.…”