Institute for Superconducting and Electronic Materials, University of Wollongong , Wollongong, NSW 2522 Australia.
ACS Nano. 2017 Feb 28;11(2):1747-1754. doi: 10.1021/acsnano.6b07644. Epub 2017 Feb 3.
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), 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 round-trip efficiency and satisfactory cycling stability, the air electrode structure and the electrocatalysts play important roles. Here, a 3D array composed of one-dimensional TiN@PtCu nanowires was synthesized and employed as a whole porous air electrode in a lithium-oxygen battery. The TiN nanowire was primarily used as an air electrode frame and catalyst support to provide a high electronic conductivity network because of the high-orientation one-dimensional crystalline structure. Meanwhile, deposited icosahedral PtCu nanocrystals exhibit highly efficient catalytic activity owing to the abundant {111} active lattice facets and multiple twin boundaries. This porous air electrode comprises a one-dimensional TiN@PtCu nanowire array that demonstrates excellent energy conversion efficiency and rate performance in full discharge and charge modes. The discharge capacity is up to 4600 mAh g along with an 84% conversion efficiency at a current density of 0.2 mA cm, and when the current density increased to 0.8 mA cm, the discharge capacity is still greater than 3500 mAh g together with a nearly 70% efficiency. This designed array is a promising bifunctional porous air electrode for lithium-oxygen batteries, forming a continuous conductive and high catalytic activity network to facilitate rapid gas and electrolyte diffusion and catalytic reaction throughout the whole energy conversion process.
非水锂-氧电池作为下一代储能系统极具应用前景，因为它具有潜在的高能量密度（高达 2-3 kW kg），超过了任何其他现有的储能系统，可用于存储可持续和清洁能源，以减少温室气体排放和不可再生化石燃料的消耗。为了实现高往返效率和令人满意的循环稳定性，空气电极结构和电催化剂起着重要作用。在此，我们合成了一种由一维 TiN@PtCu 纳米线组成的 3D 阵列，并将其用作锂-氧电池的整体多孔空气电极。TiN 纳米线主要用作空气电极框架和催化剂载体，由于其高取向一维晶体结构，提供了高电子传导网络。同时，沉积的二十面体 PtCu 纳米晶由于丰富的 {111} 活性晶格面和多个孪晶界，表现出高效的催化活性。这种多孔空气电极由一维 TiN@PtCu 纳米线阵列组成，在全放电和充电模式下表现出优异的能量转换效率和倍率性能。在电流密度为 0.2 mA cm 时，其放电容量高达 4600 mAh g，转换效率为 84%，当电流密度增加到 0.8 mA cm 时，放电容量仍大于 3500 mAh g，效率接近 70%。这种设计的阵列是一种很有前途的锂-氧电池双功能多孔空气电极，形成了连续的导电和高催化活性网络，以促进整个能量转换过程中快速的气体和电解质扩散以及催化反应。
