Adekoya David, Chen Hao, Hoh Hui Ying, Gould Tim, Balogun M-Sadeeq Jie Tang, Lai Chao, Zhao Huijun, Zhang Shanqing
Centre for Clean Environment and Energy, Gold Coast Campus, Griffith University, Gold Coast, Queensland 4222, Australia.
College of Materials Science and Engineering, Hunan University, Changsha 410082, China.
ACS Nano. 2020 Apr 28;14(4):5027-5035. doi: 10.1021/acsnano.0c01395. Epub 2020 Mar 26.
Cobalt oxide (CoO) delivers a poor capacity when applied in large-sized alkali metal-ion systems such as potassium-ion batteries (KIBs). Our density functional theory calculation suggests that this is due to poor conductivity, high diffusion barrier, and weak potassium interaction. N-doped carbon can effectively attract potassium ions, improve conductivity, and reduce diffusion barriers. Through interface engineering, the properties of CoO can be tuned composite design. Herein, a CoO@N-doped carbon composite was designed as an advanced anode for KIBs. Due to the interfacial design of the composite, K were effectively transported through the CoO@N-C composite multiple ionic pathways. The structural design of the composite facilitated increased CoO spacing, a nitrogen-doped carbon layer reduced K-ion diffusion barrier, and improved conductivity and protected the electrode from damage. Based on the entire composite, a superior capacity of 448.7 mAh/g was delivered at 50 mA/g after 40 cycles, and moreover, 213 mAh/g was retained after 740 cycles when cycled at 500 mA/g. This performance exceeds that of most metal-oxide-based KIB anodes reported in literature.
氧化钴（CoO）应用于诸如钾离子电池（KIBs）等大型碱金属离子系统时容量较低。我们的密度泛函理论计算表明，这是由于导电性差、扩散势垒高以及钾相互作用较弱所致。氮掺杂碳可以有效吸引钾离子、提高导电性并降低扩散势垒。通过界面工程，可以通过复合设计来调节CoO的性能。在此，设计了一种CoO@氮掺杂碳复合材料作为KIBs的先进负极。由于复合材料的界面设计，钾离子通过CoO@N-C复合材料的多个离子通道得以有效传输。复合材料的结构设计有助于增加CoO间距，氮掺杂碳层降低了钾离子扩散势垒，提高了导电性并保护电极免受损伤。基于整个复合材料，在50 mA/g的电流密度下循环40次后，容量达到448.7 mAh/g，此外，在500 mA/g的电流密度下循环740次后，仍保留213 mAh/g的容量。这一性能超过了文献中报道的大多数基于金属氧化物的KIB负极。
