Charge-Transfer Complex-Based Artificial Layers for Stable and Efficient Zn Metal Anodes
Peixun Xiong, Chuyuan Lin, Ying Wei, Jung‐Hui Kim, Gun Jang, Keren Dai, Lingxing Zeng, Shuping Huang, Seok Joon Kwon, Sang‐Young Lee, Ho Seok Park
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 H 2 O. 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 H 2 O 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||MnO 2 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 .