Charge-Transfer Complex-Based Artificial Layers for Stable and Efficient Zn Metal Anodes

Abstract

Herein, we report a charge-transfer complex electrolyte additive, 7,7,8,8-tetracyanoquinodimethane (TCNQ), with high Zn affinity, which was tightly adsorbed on the surface of a Zn anode to form a dense and robust interfacial complex layer and suppress the activity of H2O. As verified by comprehensive experimental and computational analyses, this complex layer could construct a Zn–Zn(TCNQ)2 Ohmic contact interface, guide rapid ion/electron transport, ameliorate electric field distribution, and inhibit the direct contact between the active H2O and Zn anode, demonstrating a dendrite-free Zn anode and facile Zn plating/stripping kinetics. Consequently, the Zn||Zn symmetrical cell exhibits a high Zn plating/stripping reversibility of over 1000 h at 20 mA cm–2 and 5 mA h cm–2 and a high depth of discharge (43%). Moreover, the Zn||MnO2 full cell delivers a high capacity of 143.3 mA h g–1 at 2000 mA g–1 even after 4000 cycles and a capacity retention of 94.7% after returning to 100 mA g–1.

Adjusting zinc deposition behaviors by a modified separator to acquire zinc anodes for aqueous rechargeable zinc-ion batteries

“…The result demonstrates that the modified thin separator can remarkably surpass most of the reported work with protective layers and modified separators, and further supports the validity of this concept of integrating the protective layer and separator. 18,31–42 Particularly, the life cycle of the Zn∥Zn symmetrical cells can exceed that of many previously reported Zn∥Zn symmetrical cells based on other separators (Table 1).…”

Dual Pre-Insertion Strategy to Achieve High-Performance Vanadium Oxide toward Advanced Cylindrical Zinc Ion Batteries

“…The Ragone plot of ZnVO·1.2H 2 O is shown in Figure S9. Compared with those of recently reported cathode materials for the AZIB, ,,,− the ZnVO·1.2H 2 O//Zn exhibits higher energy density and power density (252.5 Wh kg –1 at 173.0 W kg –1 ).”…”

Understanding the Electrical Mechanisms in Aqueous Zinc Metal Batteries: From Electrostatic Interactions to Electric Field Regulation

“…In addition, Xiong et al reported a charge-transfer complex electrolyte additive, 7,7,8,8-tetracyanoquinodimethane (TCNQ), which was tightly adsorbed on the surface of the Zn anode and constructed an ideal Zn-Zn(TCNQ) 2 -based Ohmic contact interface. [67] This interface significantly guided rapid ions/electrons transport and suppressed direct contact between H 2 O and Zn anodes.…”