A High‐Rate and Stable Quasi‐Solid‐State Zinc‐Ion Battery with Novel 2D Layered Zinc Orthovanadate Array

Abstract

Zinc-ion batteries are under current research focus because of their uniqueness in low cost and high safety. However, it is still desirable to improve the rate performance by improving the Zn (de)intercalation kinetics and long-cycle stability by eliminating the dendrite formation problem. Herein, the first paradigm of a high-rate and ultrastable flexible quasi-solid-state zinc-ion battery is constructed from a novel 2D ultrathin layered zinc orthovanadate array cathode, a Zn array anode supported by a conductive porous graphene foam, and a gel electrolyte. The nanoarray structure for both electrodes assures the high rate capability and alleviates the dendrite growth. The flexible Zn-ion battery has a depth of discharge of ≈100% for the cathode and 66% for the anode, and delivers an impressive high-rate of 50 C (discharge in 60 s), long-term durability of 2000 cycles at 20 C, and unprecedented energy density ≈115 Wh kg , together with a peak power density ≈5.1 kW kg (calculation includes masses of cathode, anode, and current collectors). First principles calculations and quantitative kinetics analysis show that the high-rate and stable properties are correlated with the 2D fast ion-migration pathways and the introduced intercalation pseudocapacitance.

3D CNTs Networks Enable MnO2 Cathodes with High Capacity and Superior Rate Capability for Flexible Rechargeable Zn–MnO2 Batteries

“…Two well separated redox peaks at 1.35 (Peak I) and 1.26–1.27 V (Peak II) versus Zn 2+ /Zn on cathodic sweeping, corresponding to stepwise H + and Zn 2+ insertion reactions, are clearly observed for all the curves (Figure S6, Supporting Information). The existence of CNTs endows both CMO and CMOP electrodes with extremely larger curve area (higher capacity) and significantly enhanced peak current density (boosted reaction kinetics) than that of MO and MOP electrodes (the inset of Figure a) . These significant enhancement in kinetic could also be observed by the discharge curves at 4 mA cm −2 (1.1 A g −1 ) in Figure b.…”

A Self‐Healing Integrated All‐in‐One Zinc‐Ion Battery

“…With the increase of current density from 0.1 to 3 A g −1 , the polarization voltage of charge/discharge profiles increases, whereas the plateaus are still obvious and a high capacity of 94 mAh g −1 is still achieved at 3 A g −1 , indicating the excellent rate capability of the integrated configuration. The power density of ZIBs can reach to 5089 W kg −1 , which is much higher than the cases of MnO 2 and hydrogel electrolyte‐based ZIBs and comparable with Zn 2 (OH)VO 4 and hydrogel electrolyte‐based ZIBs (Figure S12, Supporting Information) . Besides, after 1000 cycles at 1 A g −1 , the integrated configuration still display a high coulombic efficiency of about 100 % and a specific capacity of 77.2 mA h g −1 , which is 97.1 % of the initial capacity (79.5 mA h g −1 ) (Figure e).…”

An Electrolytic Zn–MnO2 Battery for High‐Voltage and Scalable Energy Storage

“…For example, average discharge plateaus have been reported of 0.6–0.9 V for Zn//V, 1.2–1.4 V for Zn//Mn, 1.6–1.8 V for Prussian blue analogues, and 1.4–1.8 V for Zn//Li/Na hybrids and alkaline Zn//Ni/Co‐based Zn batteries . The specific energy of Zn batteries of 70–140 Wh kg −1 remains meaningfully lower than that for Li‐ion batteries of 180–230 Wh kg −1 …”

“…3D light‐weight Zn foam (Figure S2) was applied to replace a more conventional compact Zn‐foil anode. This was done to suppress Zn dendrite formation, and improve Zn utilization and the corresponding overall energy/power density . In the initial chronoamperometry charge process at 2.2 V (Figure S1 a), the Zn 2+ and Mn 2+ ions from the electrolyte solution are, respectively, reduced to Zn on the anode and oxidized to form solid MnO 2 on the carbon fiber [Eq.…”