Lead-free perovskite ceramics, which have excellent energy storage capabilities, are attracting attention owing to their high power density and rapid charge-discharge speed. Given that the energy-storage properties of perovskite ceramic capacitors are significantly improved by doping with various elements, modifying their chemical compositions is a fundamental strategy. This study investigated the effect of Zn doping on the microstructure and energy storage performance of potassium sodium niobate (KNN)-based ceramics. Two types of powders and their corresponding ceramics with compositions of (1-x)(K,Na)NbO3-xBi(Ni2/3Ta1/3)O3 (KNN-BNT) and (1-x)(K,Na)NbO3-xBi(Ni1/3Zn1/3Ta1/3) O3 (KNN-BNZT) were prepared via solid-state reactions. The results indicate that Zn doping retards grain growth, resulting in smaller grain sizes in Zn-doped KNN-BNZT than in KNN-BNT ceramics. Moreover, the Zn-doped KNNBNZT ceramics exhibited superior energy storage density and efficiency across all x values. Notably, 0.9KNN-0.1BNZT ceramics demonstrate an energy storage density and efficiency of 0.24 J/cm3 and 96%, respectively. These ceramics also exhibited excellent temperature and frequency stability. This study provides valuable insights into the design of KNNbased ceramic capacitors with enhanced energy storage capabilities through doping strategies.

1. Introduction
2. Experimental
    2.1 에너지 저장용 KNN기반 분말 제조
    2.2 KNN기반 에너지 저장 소자 개발
    2.3 KNN기반 에너지 저장 소재 분석 및 성능 측정
3. Results and Discussion
    3.1 KNN-BNT 및 KNN-BNZT 분말 형상 및 결정구조분석
    3.2 KNN-BNT 및 KNN-BNZT 세라믹 미세구조 및 결정구조 분석
    3.3 KNN-BNT 및 KNN-BNZT 세라믹 에너지 저장 물성평가
4. Conclusion
Acknowledgement

• 김주은(경북대학교 신소재공학부 금속신소재공학과) | Jueun Kim (School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea)
• 박선화(경북대학교 탄소중립 지능형 에너지시스템 지역혁신 선도연구센터) | Seonhwa Park (Regional Leading Research Center for Smart Energy System, Kyungpook National University, Daegu 41566, Republic of Korea)
• 민유호(경북대학교 신소재공학부 금속신소재공학과) | Yuho Min (School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea) Corresponding author