슈퍼 커패시터용 카본 나노튜브 종이의 니켈 알루미늄 층상이중수산화물의 생장

Abstract

The supercapacitor is a new energy storage device falling in between traditional capacitors and batteries. It has a higher energy density than traditional capacitors and a higher power density and longer cycle life than batteries. The electrode is a vital component of the supercapacitor, and the electrode material is an important part of the electrode. Therefore, the research and development of electrode materials with good electrochemical performance plays a crucial part in the development of supercapacitors. Layered double hydroxides (LDHs) have a unique lamellar-porous structure that can use two kinds of storage mechanisms—electric double-layer capacitors (EDLCs) and Faraday pseudocapacitors—simultaneously. Besides, there are abundant raw materials and the cost is low, so LDHs have certain advantages as an electrode material for supercapacitors. However, the LDH itself is a semiconductor whose low conductivity and swelling or collapsing structure in charge/discharge cycles lead to capacity fading, thus limiting its further development in practical applications. To solve this problem, we examined current studies and applications of hydroxide and created a CNP–LDH composite of unique morphology and microstructure by means of compounding double hydroxide with carbon nanotube paper (CNP). The CNP–LDH composite has good electronic conductivity, a large specific surface area (SSA), and high mechanical strength. We conducted electrochemical performance tests and evaluations of the material as well as systematic studies on the relationship among the synthetic method, microstructural characteristics, and electrochemical performance of the material. In the research, we used the chemical liquid deposition method to prepare CNP/double hydroxide; characterized the morphology, crystal form, and composition of electrode materials by modern analytic determination methods; and tested the electrochemical performance of the material by cyclic voltammetry (CV) and the constant current charge and discharge method. The results showed that the CNP–LDH composite reached maximum specific capacities of 1861.5 F·g-1 and 1452 F·g-1 at the current densities of 2 A·g-1 and 20 A·g-1, respectively. The rate retention of the material remained at around 68.8%. The CNP–LDH composite electrode had a higher specific capacity than LDH with better cycling stability.