Multi-wall carbon nanotube-embedded lithium cobalt phosphate composites with reduced resistance for high-voltage lithium-ion batteries

• Published in: Electronic materials letters Vol. 12; no. 1; pp. 147 - 155
• Main Authors: Kim, Tae Kyoung, Rustomji, Cyrus S., Cho, Hyung-Man, Chun, Dongwon, Jung, Jae-Young, Caldwell, Elizabeth, Kim, Youngjin, Han, Jun Hyun, Jin, Sungho
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.01.2016; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; 전자/정보통신공학; carbon nanotube; charge transfer resistance; lithium cobalt phosphate; nano-composite; lithium-ion battery; embedded structure
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-015-5310-8

Lithium cobalt phosphate (LCP) is a high-voltage cathode material used in highenergy- density lithium-ion batteries. With a novel composite synthesis method, multi-wall carbon nanotube (MWCNT)-embedded LCP nanocomposites (LCPCNT composites) are synthesized to enhance the electrical conductance of LCP particles, reducing charge-transfer resistance. The LCP-CNT composites with enhanced electrical conductance approximately doubled cell capacity compared to a cell with a bare LCP cathode. The crystal structure of LCP-CNT composite particles is characterized by X-ray diffraction; the microstructures of the embedded MWCNTs inside LCP particles are confirmed by transmission and scanning electron microscopy with focused ion beam procedures. Electrochemical impedance spectroscopy shows the charge-transfer resistance of the cell with the LCP-CNT composite (1.0 wt. % CNT) cathode decreases to ~80 Ω, much smaller than the ~150 Ω charge-transfer resistance of the bare-LCP cathode cell. Based on battery test and impedance analysis, the main factors affecting the capacity increment are the reduced charge transfer resistance and the uniform distribution of MWCNTs, which is formed during the gelation step of the LCP synthesis procedure.