Pandey Gaurav, Serawat Surendra, Awasthi Kamlendra
Department of Physics, Malaviya National Institute of Technology Jaipur, Jaipur 302017, Rajasthan, India.
ACS Nanosci Au. 2024 Sep 16;4(6):399-408. doi: 10.1021/acsnanoscienceau.4c00029. eCollection 2024 Dec 18.
The development of supercapacitors is pivotal for sustainable energy storage solutions, necessitating the advancement of innovative electrode materials to supplant fossil-fuel-based energy sources. Zinc oxide (ZnO) is widely studied for use in supercapacitor electrodes because of its beneficial physicochemical properties, including excellent chemical and thermal stability, semiconducting characteristics, low cost, and environmentally friendly nature. In this study, ZnO nanorods were synthesized using a simple hydrothermal method and then combined with various Ni-based layered double hydroxides (LDHs) [NiM'-LDHs (M' = Mn, Co, and Fe)] to improve the electrochemical performance of the ZnO nanorods. These LDHs are well-known for their outstanding electrochemical and electronic properties, high specific capacitance, and efficient dispersion of cations within host nanolayers. The synthesized composites ZnO@NiMn-LDH, ZnO@NiCo-LDH, and ZnO@NiFe-LDH exhibit enhanced specific capacitances of 569.3, 284.6, and 133.0 F/g, respectively, at a current rate of 1 A/g, outperforming bare ZnO (98.4 F/g). Notably, ZnO@NiMn-LDH demonstrates superior electrochemical performance along with a capacitance retention of 76%, compared to ZnO@NiCo-LDH (58%), ZnO@NiFe-LDH (49%), and bare ZnO (23%) over 5000 cycles. Furthermore, an asymmetric supercapacitor (ASC) was developed by using ZnO@NiMn-LDH as the positive electrode and activated carbon (AC) as the negative electrode to assess its practical applicability. The fabricated ASC (ZnO@NiMn-LDH//AC) demonstrated a specific capacitance of 45.22 F/g at a current rate of 1 A/g, an energy density of 16.08 W h/kg at a power density of 798.8 W/kg, and a capacitance retention of 75% over 5000 cycles. These findings underscore the potential of the composite formation of ZnO with Ni-based LDHs in advancing the efficiency and durability of supercapacitors.
超级电容器的发展对于可持续储能解决方案至关重要，因此需要开发创新的电极材料来取代基于化石燃料的能源。氧化锌（ZnO）因其有益的物理化学性质，包括优异的化学和热稳定性、半导体特性、低成本和环境友好性，而被广泛研究用于超级电容器电极。在本研究中，采用简单的水热法合成了ZnO纳米棒，然后将其与各种镍基层状双氢氧化物（LDHs）[NiM'-LDHs（M' = Mn、Co和Fe）]复合，以改善ZnO纳米棒的电化学性能。这些LDHs以其出色的电化学和电子性能、高比电容以及阳离子在主体纳米层内的有效分散而闻名。合成的复合材料ZnO@NiMn-LDH、ZnO@NiCo-LDH和ZnO@NiFe-LDH在1 A/g的电流速率下分别表现出增强的比电容，分别为569.3、284.6和133.0 F/g，优于裸ZnO（98.4 F/g）。值得注意的是，与ZnO@NiCo-LDH（58%）、ZnO@NiFe-LDH（49%）和裸ZnO（23%）相比，ZnO@NiMn-LDH在5000次循环中表现出优异的电化学性能，电容保持率为76%。此外，通过使用ZnO@NiMn-LDH作为正极和活性炭（AC）作为负极，开发了一种不对称超级电容器（ASC），以评估其实际适用性。制备的ASC（ZnO@NiMn-LDH//AC）在1 A/g的电流速率下表现出45.22 F/g的比电容，在798.8 W/kg的功率密度下能量密度为16.08 W h/kg，在5000次循环中的电容保持率为75%。这些发现强调了ZnO与镍基LDHs复合形成在提高超级电容器效率和耐久性方面的潜力。
