K⁺ pre-intercalated manganese dioxide with enhanced Zn²⁺ diffusion for high rate and durable aqueous zinc-ion batteries

Abstract

α-K0.19MnO2 nanotubes with high K+ content as cathodes for zinc-ion batteries show high capacity, excellent rate capability and cycling stability.

Defect Engineering in Manganese‐Based Oxides for Aqueous Rechargeable Zinc‐Ion Batteries: A Review

“…Reproduced with permission. [ 82 ] Copyright 2019, Royal Society of Chemistry. e) Structural illustration of zinc ion stabilized MnO 2 .…”

“…Liu et al reported a tunnel‐structure α‐MnO 2 with high preintercalated K + content (α‐K 0.19 MnO 2 ) as a superior cathode for ZIB. [ 82 ] The tunnel structure was shown to have transformed into layer structure after cycling. As such, the preintercalated K + were introduced into the layer space as pillars which could help to stabilize the layer structures.…”

“…[ 81 ] Liu and co‐workers synthesized a tunnel‐structured MnO 2 nanotube with a high preintercalated K + content by a self‐sacrificial template method, which involved a neutral hydrothermal process to synthesize δ‐MnO 2 nanotubes using carbon nanofiber as both template and reactant, and then transformed into α‐MnO 2 nanotubes via an annealing process. [ 82 ] During the neutral hydrothermal process, the concentration of H + is low, which does affect the K + intercalation. This phenomenon is beneficial to the insertion of K + into the MnO 2 host.…”

“…Liu et al demonstrated K + cations preintercalated α‐MnO 2 as a good cathode for Zinc ions storage. [ 82 ] During electrochemical tests, the water‐solvated H + first intercalated into α‐MnO 2 followed by the insertion of Zn 2+ which transformed MnO 2 from a tunnel structure into a layer structure. Meantime, the preintercalated K cations rearranged to be exist in the layer spacing which functioned as pillars to strengthen the layered structures and enabled a reversible H + and Zn 2+ diffusion for the insertion/extraction process.…”

Zn2+ Pre‐Intercalation Stabilizes the Tunnel Structure of MnO2 Nanowires and Enables Zinc‐Ion Hybrid Supercapacitor of Battery‐Level Energy Density

“…[ 17 ] Liu et al have reported that the structural stability can be improved by pre‐intercalated K + into the tunnel structure α‐MnO 2 . [ 18 ] Although the cycling performance was improved to a certain degree, the structure still undergoes an unstable transformation (i.e., transformation into layered structure δ‐MnO 2 ), when further intercalated in Zn 2+ . Therefore, structural stability is one of the key factors in the design of Zn‐HSCs electrode materials.…”