Materials Science and Engineering Program and Texas Materials Institute, the University of Texas at Austin, Austin, Texas 78712, USA.
Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 689-798 Ulsan, South Korea.
Nat Commun. 2017 Apr 26;8:14589. doi: 10.1038/ncomms14589.
Undesired electrode-electrolyte interactions prevent the use of many high-energy-density cathode materials in practical lithium-ion batteries. Efforts to address their limited service life have predominantly focused on the active electrode materials and electrolytes. Here an advanced three-dimensional chemical and imaging analysis on a model material, the nickel-rich layered lithium transition-metal oxide, reveals the dynamic behaviour of cathode interphases driven by conductive carbon additives (carbon black) in a common nonaqueous electrolyte. Region-of-interest sensitive secondary-ion mass spectrometry shows that a cathode-electrolyte interphase, initially formed on carbon black with no electrochemical bias applied, readily passivates the cathode particles through mutual exchange of surface species. By tuning the interphase thickness, we demonstrate its robustness in suppressing the deterioration of the electrode/electrolyte interface during high-voltage cell operation. Our results provide insights on the formation and evolution of cathode interphases, facilitating development of in situ surface protection on high-energy-density cathode materials in lithium-based batteries.
不理想的电极-电解质相互作用阻止了许多高能密度阴极材料在实用锂离子电池中的应用。为了解决它们有限的使用寿命问题，人们主要关注的是活性电极材料和电解质。在这里，对一种模型材料——富镍层状锂过渡金属氧化物进行了先进的三维化学和成像分析，揭示了在常见的非水电解质中，导电碳添加剂（炭黑）驱动的阴极界面相的动态行为。感兴趣区域敏感二次离子质谱表明，最初在没有电化学偏压施加的情况下在炭黑上形成的阴极-电解质界面相，通过表面物种的相互交换，很容易通过相互交换来使阴极颗粒钝化。通过调整界面相的厚度，我们证明了它在抑制高压电池运行过程中电极/电解质界面恶化方面的稳健性。我们的结果提供了对阴极界面相形成和演化的深入了解，有助于在基于锂的电池中高能密度阴极材料的原位表面保护的发展。
