Layered-MnO2 Nanosheet Grown on Nitrogen-Doped Graphene Template as a Composite Cathode for Flexible Solid-State Asymmetric Supercapacitor

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• 作者：Yongchuan Liu ; Xiaofei Miao ; Jianhui Fang ; Xiangxin Zhang ; Sujing Chen ; Wei Li ; Wendou Feng ; Yuanqiang Chen ; Wei Wang ; Yining Zhang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 2, 2016
• 年：2016
• 卷：8
• 期：8
• 页码：5251-5260
• 全文大小：704K
• ISSN：1944-8252

文摘

Flexible solid-state supercapacitors provide a promising energy-storage alternative for the rapidly growing flexible and wearable electronic industry. Further improving device energy density and developing a cheap flexible current collector are two major challenges in pushing the technology forward. In this work, we synthesize a nitrogen-doped graphene/MnO₂ nanosheet (NGMn) composite by a simple hydrothermal method. Nitrogen-doped graphene acts as a template to induce the growth of layered δ-MnO₂ and improves the electronic conductivity of the composite. The NGMn composite exhibits a large specific capacitance of about 305 F g^–1 at a scan rate of 5 mV s^–1. We also create a cheap and highly conductive flexible current collector using Scotch tape. Flexible solid-state asymmetric supercapacitors are fabricated with NGMn cathode, activated carbon anode, and PVA–LiCl gel electrolyte. The device can achieve a high operation voltage of 1.8 V and exhibits a maximum energy density of 3.5 mWh cm^–3 at a power density of 0.019 W cm^–3. Moreover, it retains >90% of its initial capacitance after 1500 cycles. Because of its flexibility, high energy density, and good cycle life, NGMn-based flexible solid state asymmetric supercapacitors have great potential for application in next-generation portable and wearable electronics.