Effects of the removal rate of impurity on the electrochemical properties of resynthesized Li[Ni1-x-yCoxMny]O2 cathode active materials from spent lithium-ion battery leachate = 폐리튬이온배터리 침출수 내의 불순물 원소 제거 정도에 따른 재합성 양극활물질 Li[Ni1-x-yCoxMny]O2의 전기화학적 특성

다국어 초록 (Multilingual Abstract)

Various impurities such as Cu, Al, and Fe can be incorporated in the leachate of spent lithium-ion batteries (LIB) after a conventional acidic leaching process. Here, we synthesize Fe/Al co-modified Ni-rich Li[Ni1-x-yCoxMny]O2 (NCM) cathode materials via a coprecipitation reaction for Fe doping and the subsequent calcination process for additional Al doping. The purpose of this work is to seek a potential of utilizing the positive effects of impurity elements for improving the LIB performance of Ni-rich NCM. The physicochemical properties of cathode materials are compared by scanning electron microscopy, energy dispersive spectroscopy, inductively coupled plasma optical emission spectroscopy and X-ray diffraction analysis. Electrochemical analyses including galvanostatic intermittent titration technique, differential capacity curves from cycling data are systematically performed to assess the effects of the sequential doping processes. It is found that an Al doping content of 1% in Fe-doped NCM is optimal in terms of rate and cycle performances. This study also proposes a rational design for upgrading the resynthesized Ni-rich NCM cathode materials from the leachate of spent LIBs. In addition, resynthesized precursors from the actual leachate, purified precursors, and a control sample are synthesized via co-precipitation method. The structure and electrochemical properties of the resynthesized precursors and the corresponding cathode materials are examined.

목차 (Table of Contents)

• Contents
• Ⅰ. Introduction 1
• Ⅱ. Experimental 6
• III. The effects of Fe/Al co-modified Ni-rich Li[Ni1-x-yCoxMny]O2 for enhancing electrochemical performance 12
• 1. Physicochemical characteristics 12
• 2. Electrochemical characteristics 20
• IV. Properties of resynthesized Li[Ni0.6Co0.2Mn0.2]O2 cathode active materials depending on the pH during the precipitation of impurities in Li-ion battery leachate 28
• 1. Purification characterization 28
• 2. Physicochemical characteristics 31
• 3. Electrochemical characteristics 38
• V. Conclusions 43
• Ⅳ. References 46