(Invited) Some Progress in Understanding the Chemical and Charge Distribution in Layered Oxides

Abstract

Layered oxides have dominated the development of cathode materials for lithium and sodium ion batteries. To date, most studies of layered oxides have focused on controlling the global structural and chemical properties rather than improving the local chemical and charge distribution. We believe that there is a large space to improve the performance of these decades-old cathode materials from a different perspective. Can we improve the utility of battery particles throughout the electrode? Can we improve the %utilization of individual battery particles? Answering these questions lead us to investigate battery materials with particle specificity. In this presentation, we will discuss our recent progress in (1) controlling the chemical distribution in primary and secondary particles, and (2) probing the charge distribution with sensitivity to the grain crystallographic orientation in polycrystalline layered oxides. For the first one, we will highlight that tailoring the dopant distribution in Co-free Li layered cathodes can maximize the functions of individual doping elements, improving the bulk and surface stability. In addition, we will discuss how engineering the distribution of transition metals in secondary particles may provide some unexpected performance outcomes. For the second one, we will elucidate the spatially resolved charge distribution in lithium layered oxides with different grain crystallographic arrangements and establish a model to quantify their charge distributions. We will highlight that the crystallographic orientation-guided redox reaction governs the charge distribution in the local charged nanodomains.