Controllable Synthesis of Hollow Bipyramid β-MnO₂ and Its High Electrochemical Performance for Lithium Storage

Abstract

Three types of MnO2 nanostructures, viz., α-MnO2 nanotubes, hollow β-MnO2 bipyramids, and solid β-MnO2 bipyramids, have been synthesized via a simple template-free hydrothermal method. Cyclic voltammetry and galvanostatic charge/discharge measurements demonstrate that the hollow β-MnO2 bipyramids exhibit the highest specific capacity and the best cyclability; the capacity retains 213 mAh g(-1) at a current density of 100 mA g(-1) after 150 cycles. XRD patterns of the lithiated β-MnO2 electrodes clearly show the expansion of lattice volume caused by lithiation, but the structure keeps stable during lithium insertion/extraction process. We suggest that the excellent performance for β-MnO2 can be attributed to its unique electrochemical reaction, compact tunnel-structure and hollow architecture. The hollow architecture can accommodate the volume change during charge/discharge process and improve effective diffusion paths for both lithium ions and electrons.

Hydrothermal synthesis of α-MnO2 and β-MnO2 nanorods as high capacity cathode materials for sodium ion batteries

“…Two redox peaks at 2.36 and 2.66 V correspond to Na + insertion into/ extraction from the b-MnO 2 crystal structure. 29,30 The cycling performances of a-MnO 2 and b-MnO 2 nanorods are shown in Fig. 5.…”

Two-Dimensional β-MnO2 Nanowire Network with Enhanced Electrochemical Capacitance

“…Compared to the other MnO 2 , β-MnO 2 has a rutile-type tetragonal symmetry (P4 2 /mnm) with a distorted hexagonal-close packed oxygen array, where edge-sharing MnO 6 octahedra stacks and forms 1 × 1 (0.23 nm × 0.23 nm) tunnels28. β-MnO 2 received much attention in lithium batteries and showed good performances293031. However, few investigations have been concentrated on the utilization of β-MnO 2 for electrochemical capacitors since the narrowest (1 × 1) tunnel in its structure makes it difficult for ions to diffuse into bulk upon electrochemically intercalating, resulting in that conventional crystalline β-MnO 2 usually exhibits poor electrochemical activities2930.…”

Challenges and perspectives for manganese‐based oxides for advanced aqueous zinc‐ion batteries

“…Some studies have successfully proved that β-MnO 2 has excellent zinc storage performance. [86][87][88][89] A previous study by Kang et al 90 revealed that massive β-MnO 2 delivered low electrochemical activity in ZIBs. In a subsequent work, Kang et al 91 achieved reversible insertion/extraction of Zn 2+ ions into/from β-MnO 2 with a porous framework.…”

“…And the c ‐axis of β‐MnO 2 consists of single chains of [MnO 6 ] octahedral units by sharing corners (Figure 4A). Some studies have successfully proved that β‐MnO 2 has excellent zinc storage performance . A previous study by Kang et al revealed that massive β‐MnO 2 delivered low electrochemical activity in ZIBs.…”