Graphene-oxide-wrapped ZnMn₂O₄ as a high performance lithium-ion battery anode

Abstract

Cation distribution between tetrahedral and octahedral sites within the ZnMn2O4 spinel lattice, along with microstructural features, is affected greatly by the temperature of heat treatment. Inversion parameter can easily be tuned, from 5 to 19%, depending on the annealing temperature. The upper limit of inversion is found for T= 400 °C as confirmed by X-ray powder diffraction and Raman spectroscopy. Excellent battery behavior is found for samples annealed at lower temperatures; after 500 cycles the specific capacities for as-prepared ZnMn2O4 is 909 mAh/g, while ZnMn2O4 heat-treated at 300 °C shows 1179 mAh/g which amounts to 101 % of its initial capacity. Despite excellent performance of sample processed at 300 °C at lower charge/discharge rates (100 mAh/g), a drop in the specific capacity is observed with rate increase. This issue is solved by graphene oxide wrapping; specific capacity obtained after 400th cycle for graphene oxide wrapped ZnMn2O4 heat-treated at 300 °C is 799 mAh/g at charge/discharge rate 0.5 A/g, which is higher by factor 6 compared to sample without graphene oxide wrapping.

What Happens to MnO2 When It Comes in Contact with Zn2+? An Electrochemical Study in Aid of Zn/MnO2‐Based Rechargeable Batteries

“…The Raman spectrum of EDM grown from the solution containing 4 mM MnSO 4 and 0.1 M ZnSO 4 (Figure 8, blue plot) is different from that of EDM electrodeposited in the absence of Zn 2+ . The bands at ≈318, 370, and 668 cm −1 are compatible with tetragonal spinel ZnMn 2 O 4 [ 62–67 ] and those at ≈ 500, 574, and 658 cm −1 with δ‐MnO 2 . [ 68 ] Spectral assignment on the basis of the literature cannot be definitive, and a rigorous structural analysis is beyond the scope of this paper, but the profoundly modified pattern witnesses a strong effect of Zn 2+ on the electrocrystallization of EDM.…”

A ternary oxygen-vacancy abundant ZnMn2O4/MnCO3/nitrogen-doped reduced graphene oxide hybrid towards superior-performance lithium storage

“…In addition, the zinc ions in ZnMn 2 O 4 crystals are exposed to large electrostatic repulsive forces when moving, thus making them move extremely slowly and seriously hindering the electrochemical performance of ZnMn 2 O 4 . 19 Chen et al found that reducing the size of the active material to the nanoscale effectively improved ion diffusion and electron migration, leading to significantly shorter diffusion paths for the guest ions, generating abundant lattice defects 20 and thus improving the electrochemical performance. Meanwhile, they proposed that N-doping of graphene exhibited good conductivity.…”

Fabrication of a Flexible Aqueous Textile Zinc-Ion Battery in a Single Fabric Layer

“…In addition, the assembly of ZIBs can be done in air, offering reduced fabrication complexity. A ZIB typically consists of a zinc metal anode, a porous separator with a low hazard electrolyte and various metal oxides such as V 2 O 5 (Javed et al, 2020), ZnMn 2 O 4 (Sun et al, 2017), manganese (IV) oxide (MnO 2 ) [Jiao et al, 2020) and manganese (II, III) oxide (Mn 3 O 4 ) (Hao et al, 2018)] as the cathode. The metal zinc anode has a high theoretical capacity of 820 mAh g −1 (Wang F. et al, 2018).…”