Dendrite‐Free Zinc Deposition Induced by Multifunctional CNT Frameworks for Stable Flexible Zn‐Ion Batteries

• Published in: Advanced materials (Weinheim) 2019-09, Vol.31 (36), p.e1903675-n/a
• Main Authors: Zeng, Yinxiang, Zhang, Xiyue, Qin, Ruofei, Liu, Xiaoqing, Fang, Pingping, Zheng, Dezhou, Tong, Yexiang, Lu, Xihong
• Format: Article
• Language: English
• Subjects: Anodes; Carbon nanotubes; dendrite‐free; Dendritic structure; Electric fields; Energy storage; flexible; Low voltage; Manganese dioxide; Materials science; Morphology; Nucleation; Plating; Storage batteries; Storage systems; Stripping; Zinc; Zn anodes; Zn‐ion batteries
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201903675

The current boom of safe and renewable energy storage systems is driving the recent renaissance of Zn‐ion batteries. However, the notorious tip‐induced dendrite growth on the Zn anode restricts their further application. Herein, the first demonstration of constructing a flexible 3D carbon nanotube (CNT) framework as a Zn plating/stripping scaffold is constituted to achieve a dendrite‐free robust Zn anode. Compared with the pristine deposited Zn electrode, the as‐fabricated Zn/CNT anode affords lower Zn nucleation overpotential and more homogeneously distributed electric field, thus being more favorable for highly reversible Zn plating/stripping with satisfactory Coulombic efficiency rather than the formation of Zn dendrites or other byproducts. As a consequence, a highly flexible symmetric cell based on the Zn/CNT anode presents appreciably low voltage hysteresis (27 mV) and superior cycling stability (200 h) with dendrite‐free morphology at 2 mA cm−2, accompanied by a high depth of discharge (DOD) of 28%. Such distinct performance overmatches most of recently reported Zn‐based anodes. Additionally, this efficient rechargeability of the Zn/CNT anode also enables a substantially stable Zn//MnO2 battery with 88.7% capacity retention after 1000 cycles and remarkable mechanical flexibility. A flexible 3D carbon nanotube (CNT) network is proposed as a highly conductive skeleton for Zn deposition to achieve a dendrite‐free Zn/CNT anode. Taking the advantages of low Zn nucleation overpotential and homogeneously distributed electric field, the Zn/CNT anode exhibits a prolonged cycling life over 200 h at high depth of discharge of 28%, which also enables a stable Zn//MnO2 battery.