鋰離子二次電池多成份層狀陰極材料之製備與特性分析

Preparation and Electrochemical Characterization of Multicomponent Layered Cathode Materials for Lithium Ion Secondary Batteries

沈柏君(Bo-Jun Shen)

指導教授 ： 呂宗昕

國立臺灣大學/工學院/化學工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.00048

摘要

本研究成功利用微波水熱法合成層狀材料LiNi1/3Co1/3Mn1/3O2，在800oC溫度下可得良好結晶相之粉體。此法和目前最常用的共沉澱法互相比較，微波水熱法不僅僅節省了許多共沉澱法的複雜步驟和總反應時間，而且還有效地減少粉體的平均粒徑大小，電性的結果皆顯示利用微波水熱的合成粉體比共沉澱法還要優良。

而當進一步改變微波溫度以觀察其影響時，發現當微波反應溫度增加時，先驅物粉體的凝團程度減少，導致許多二次粒子皆轉變成粉體粒徑較小的一次粒子，此結果進而促使煆燒後層狀粉體的比表面積增加，亦增強許多粉體電化學特性上的表現。當微波溫度達到180oC時，其最後產物的粉體在0.1C-rate測試條件下達到約170 mAh/g的高電容量，10圈之後的保留值依然有98.5%，從EIS測試中，可以算出此粉體擁有高鋰離子擴散係數，此結果有助於高速充放電的特性測試。因此可以從結果中得到一個重要的結論：對於微波水熱系統來說，溫度是控制粉體的一個重要的參數，導致粉體表現出不同的電化學特性。

關鍵字

鋰離子二次電池 ； 陰極材料 ； 微波水熱 ； LiNi1/3Co1/3Mn1/3O2氧化物 ； 微波輻射溫度

並列摘要

LiNi1/3Co1/3Mn1/3O2 powders have been successfully synthesized through a developed microwave-hydrothermal (M-H) process. In comparison with the co-precipitation process having complicated steps, the microwave-hydrothermal process not only reduced the reaction time for preparing LiNi1/3Co1/3Mn1/3O2, but also effectively decreased the average particle size of powders. The results of electrochemical performance show that the sample prepared by the microwave hydrothermal process is superior to that by the co-precipitation method.

In order to study the influences of microwave-radiated temperatures on the morphology of particles, the temperature during the reaction was changed. When the microwave-radiated temperature increased from 100oC to 180oC, the particles exhibited a less agglomerated morphology and reduced particle size. Increasing the microwave-radiated temperatures of preparation for precursors not only increased the surface area of LiNi1/3Co1/3Mn1/3O2 powders but also enhanced the electrochemical performances. When the temperature of microwave-hydrothermal treatment was raised to 180oC, the final products of LiNi1/3Co1/3Mn1/3O2 exhibited significantly improved characteristics. It showed that the discharge capacity was approximately 170 mAh/g and the retention was 98.5% after 10 cycles. The prepared materials also exhibited high lithium ion diffusion coefficient and good rate capability in EIS tests.

並列關鍵字

Lithium ion battery ； cathode materials ； microwave hydrothermal ； LiNi1/3Co1/3Mn1/3O2 oxide ； microwave radiation temperature

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