■ 제 목: Innovating layered cathode materials through the mechanistic understanding of its disorders

■ 연 사: 강용묵 교수 (고려대학교 신소재공학부)

■ 일 시: 2025년 5월 20일(화) 오후 4시             

■ 장 소: 응용공학동 1층 영상강의실 

■ Host: 정연식 교수

■ Abstract : The properties of solid materials are intricately related to their structures, and traditional research has leveraged a crystallographic approach based on space groups to identify the structure-property relationships. This method projects structures into reciprocal space based on the periodicity of unit cells, yet in reality, solid materials frequently exhibit various disorder, deviating from the ideal crystal structure model. Cathode materials, for instance, contain various disorders, not only the ones introduced during synthesis but also the others that arises due to the repetitive formation and disappearance of vacancies and oxidation/reduction during the electrochemical cycling. As various disorders manifest and their contribution to structure gets more significant, the structure-property relationship becomes vaguer from the perspective of traditional crystallographic approaches. With the increasing performance requirements for secondary batteries, improving cathode material performance has become crucial. However, more unclear structure-property relationship has imposed significant limitations on the further development of cathode materials. Consequently, a new approach is essential to analyze the structure-property relationships, taking into account the inevitable disorder occurring within cathode materials. In this presentation, we explore the chemical origins that induce disorder and investigate how disorder is introduced and managed within materials, and identifying the local interactions that drive property induction. We examine how enhancing carrier ion kinetics and controlling oxidation-reduction behavior through the introduction of disorder can boost energy and power density. Additionally, we discuss how improved reversibility between transition metals and oxygen, facilitated by disorder, can enhance cycle performance. This approach allows us to redefine the relationship between disorder, structure, and properties. Based on this perspective, we introduce a study that details the mechanism by which aluminum doping enhances oxygen stability in materials. We present complementary mRIXS/OEMS analytical methodologies to evaluate oxygen stability and demonstrate how aluminum doping improves the oxygen stability of high-Ni NCM cathode materials, leading to enhanced structural stability and better cycle performance.