A Superior δ-MnO₂ Cathode and a Self-Healing Zn-δ-MnO₂ Battery

Abstract

While α-MnO2 has been intensively studied for zinc batteries, δ-MnO2 is usually believed to be more suitable for ion storage with its layered structure. Unfortunately, the extraordinary Zn ion storage performance that δ-MnO2 should exhibit has not yet been achieved due to the frustrating structural degradation during charge–discharge cycles. Here, we found the Na ion and water molecules pre-intercalation can effectively activate stable Zn ion storage of δ-MnO2. Our results reveal that the resulted Zn//pre-intercalated δ-MnO2 battery delivers an extraordinarily high-rate performance, with a high capacity of 278 mAh g–1 at 1 C and up to 20 C, and a high capacity of 106 mAh g–1 can still be measured. The capacity retention is as high as 98% after charged–discharged up to 10,000 cycles benefiting from smooth Zn ion diffusion in the pre-intercalated structure. Further in situ /ex situ characterization confirms the superfast Zn ion diffusion in the pre-intercalated structure at room temperature. In addition, utilizing the well-chosen electrode material and modified polyurethane shell, we fabricated a quasi-solid-state healable Zn-δ-MnO2, which can be self-healed after multiple catastrophic damages, emphasizing the advanced features of aqueous Zn ion battery for wearable applications.

Layered Ca0.28MnO2·0.5H2O as a High Performance Cathode for Aqueous Zinc‐Ion Battery

“…The O 1s spectrum (Figure 1c) shows that three obvious peaks with binding energy of 529.1, 530.7, and 532.4 eV, corresponding to MnOMn bond, MnOH bond, and HOH bond, respectively. [ 7 ] The presence of MnOH bond and HOH bond indicates that a significant amount of crystal water has been intercalated into CaMnO. In addition, the detailed composition of Mn element is investigated by Mn 2p spectrum.…”

“…[ 3 ] Among the various types of cathode materials, MnO 2 , with higher capacity (>250 mAh g −1 ), higher voltage (1.3–1.5 V), and various crystallographic polymorphs (α‐, β‐, γ‐, δ‐, λ‐, and ε‐type), is widely researched in ZIBs. [ 4,5 ] Especially, layered‐type δ‐MnO 2 (birnessite‐type manganese oxides) exhibits a large interspacing channel (≈0.7 nm), [ 6,7 ] which is much more suitable for fast and reversible (de‐)intercalation of Zn ions. Unfortunately, the Zn//δ‐MnO 2 battery system suffers from bad electrochemical performance, including significant capacity fading and poor rate capability.…”

Unravelling H+/Zn2+ Synergistic Intercalation in a Novel Phase of Manganese Oxide for High‐Performance Aqueous Rechargeable Battery

“…Two pairs of redox peaks denoted as peak 1, 2, 3, and 4 are observed (Figure d), indicating two charge/discharge redox reactions. The charge storage kinetics are identified by the relationship between the current value of peaks ( i ) and the scanning rates (ν): i = a·ν b , where a and b are variable values . The value of b is in a range of 0.5 to 1: when b = 0.5, the solid diffusion of H + /Zn 2+ dictates the charge/discharge process; when b = 1, the surface electrochemical capacitive adsorption of H + /Zn 2+ is predominant.…”

“…The charge storage kinetics are identified by the relationship between the current value of peaks (i) and the scanning rates (ν): i = a·νb, where a and b are variable values. [27][28][29] The value of b is in a range of 0.5 to 1: when b = 0.5, the solid diffusion of H + /Zn 2+ dictates the charge/ discharge process; when b = 1, the surface electrochemical capacitive adsorption of H + /Zn 2+ is predominant. The dependence curves and corresponding fitting curves between log (i) and log (ν) for the four redox peaks are plotted in Figure 5e.…”

A Durable Na0.56V2O5 Nanobelt Cathode Material Assisted by Hybrid Cationic Electrolyte for High‐Performance Aqueous Zinc‐Ion Batteries

“…According to previous literatures, the electrochemical reaction can be described as follows [Eq. (1)]: [28,[34][35][36][37][38][39][40] x Zn 2þ þ Na 0:56 V 2 O 5 þ 2x e À $ Zn x Na 0:56 V 2 O 5 (1) This reaction reflects the reversible insertion/extraction of Zn 2 + in the NVO. The capacitive effect of battery is calculated by Equations (2) and (3):…”