Ran Jiaqi, Guo Xiaosong, Liu Peitao, Peng Shanglong, Gao Xiaoping, Gao Daqiang
Key Laboratory for Magnetism and Magnetic Materials of MOE, Key Laboratory of Special Function Materials and Structure Design of MOE, Lanzhou University, Lanzhou 730000, People's Republic of China.
Nanotechnology. 2019 Oct 25;30(43):435701. doi: 10.1088/1361-6528/ab31bf. Epub 2019 Jul 13.
It is essentially important to improve the performance of Zn-air batteries by studying bifunctional catalysts for oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) with low-cost, high-efficiency and high-stability properties. Here, CoNi nanoparticles embedded in the bamboo-like N-doped carbon tubes (Co Ni @NC) were synthesized, where the optimized catalyst of CoNi@NC exhibits superior bifunctional electrocatalytic activity, showing a low overpotential of 300 mV under the current density of 10 mA cm for OER and a large limiting current density of 3.76 mA cm under 0.40 V for ORR in an alkaline solution. In addition, the CoNi@NC also shows excellent electrocatalytic activity in acidic and neutral solutions. Importantly, primary Zn-air batteries based on CoNi@NC affords an excellent specific capacity of 834 mAh/g with a discharge potential of 1.25 V at 5 mA cm. A rechargeable Zn-air battery assembled with CoNi@NC shows excellent cycling stability, where the first discharge and charge voltages reach 1.21 and 2.00 V under 1 mA cm, respectively. This finding provides a simple synthesis approach, which allows one to construct bifunctional catalysts based on metal@NC for future energy conversion and storage devices.
通过研究具有低成本、高效率和高稳定性的氧析出反应（OER）和氧还原反应（ORR）双功能催化剂来提高锌空气电池的性能至关重要。在此，合成了嵌入竹状氮掺杂碳管中的钴镍纳米颗粒（CoNi@NC），其中优化后的CoNi@NC催化剂表现出优异的双功能电催化活性，在碱性溶液中，对于OER在10 mA cm的电流密度下过电位低至300 mV，对于ORR在0.40 V下极限电流密度高达3.76 mA cm。此外，CoNi@NC在酸性和中性溶液中也表现出优异的电催化活性。重要的是，基于CoNi@NC的一次锌空气电池在5 mA cm时具有834 mAh/g的优异比容量和1.25 V的放电电位。用CoNi@NC组装的可充电锌空气电池显示出优异的循环稳定性，在1 mA cm下首次放电和充电电压分别达到1.21和2.00 V。这一发现提供了一种简单的合成方法，可用于构建基于金属@NC的双功能催化剂，用于未来的能量转换和存储设备。
