Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW, 2522, Australia.
School of Materials and Metallurgy, Northeastern University, Shenyang, 110004, China.
Small. 2015 Jun;11(23):2817-24. doi: 10.1002/smll.201403535. Epub 2015 Feb 16.
The nonaqueous lithium oxygen battery is a promising candidate as a next-generation energy storage system because of its potentially high energy density (up to 2-3 kW kg(-1)), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high energy density, long cycling stability, and low cost, the air electrode structure and the electrocatalysts play important roles. Here, a metal-free, free-standing macroporous graphene@graphitic carbon nitride (g-C3N4) composite air cathode is first reported, in which the g-C3N4 nanosheets can act as efficient electrocatalysts, and the macroporous graphene nanosheets can provide space for Li2O2 to deposit and also promote the electron transfer. The electrochemical results on the graphene@g-C3N4 composite air electrode show a 0.48 V lower charging plateau and a 0.13 V higher discharging plateau than those of pure graphene air electrode, with a discharge capacity of nearly 17300 mA h g(-1)(composite) . Excellent cycling performance, with terminal voltage higher than 2.4 V after 105 cycles at 1000 mA h g(-1)(composite) capacity, can also be achieved. Therefore, this hybrid material is a promising candidate for use as a high energy, long-cycle-life, and low-cost cathode material for lithium oxygen batteries.
非水锂氧电池作为下一代储能系统具有很大的发展潜力，因为它具有潜在的高能量密度（高达 2-3kWkg-1），超过了任何其他现有的储能系统，用于储存可持续和清洁能源，以减少温室气体排放和不可再生化石燃料的消耗。为了实现高能量密度、长循环稳定性和低成本，空气电极结构和电催化剂起着重要的作用。在这里，首次报道了一种无金属、独立式的大孔石墨烯/石墨相氮化碳（g-C3N4）复合空气阴极，其中 g-C3N4 纳米片可以作为高效的电催化剂，而大孔石墨烯纳米片可以提供空间让 Li2O2 沉积，也可以促进电子转移。在石墨烯/g-C3N4 复合空气电极上的电化学结果表明，与纯石墨烯空气电极相比，充电平台低 0.48V，放电平台高 0.13V，放电容量接近 17300mA h g-1（复合材料）。还可以实现优异的循环性能，在 1000mA h g-1（复合材料）容量下经过 105 次循环后，端电压高于 2.4V。因此，这种混合材料是一种很有前途的候选材料，可用作高能量、长循环寿命、低成本的锂氧电池阴极材料。
