CrFeMnTiVZr高熵儲氫合金 用作鎳氫電池負極之研究

Hydrogen Storage CrFeMnTiVZr as Negative Electrode Material in Nickel-Metal Hydride Cell

張翊凡(I-Fan Chang)

指導教授 ： 吳振名 ； 陳瑞凱

國立清華大學/工學院/材料科學工程學系/碩士(2014年)

摘要

本研究以六元AB2 C14 Laves相CrFeMnTiVZr高熵合金為主體，對各元素進行成分的調變，設計出包括加鈷的等莫耳七元合金在內的，拾數個非等莫耳與等莫耳合金(以下簡稱本合金)，探討單一元素的添加或減少對鎳氫電池的放電容量及循環壽命的影響。真空電弧熔煉製備鑄造態塊狀合金，擊碎，325 mesh過篩後，活化消除毒化層，並與PTFE混漿，製作成負極，搭配氫氧化鎳正極，以30 wt % KOH水溶液為電解液，自行組裝成鎳氫電池，使用電池自動化充放電系統，設定充放電條件，記錄電壓、電流、時間，計算放電容量及循環壽命。
本合金各元素的成分調配，影響許多重要性能，包含吸放氫能力、熱力學性質、抗氧化及腐蝕能力、微粉化、放電動力學、催化特性、氣體再結合能力、循環壽命等。初步結論，本研究放電表現最好的為Fe1.5試片，最高放電電容量可達143.34 mAh/g；循環壽命表現最好的為Mn0，在經過30個cycles充放電循環測試後，放電電容量仍可達最高放電容量的五成；七元合金比六元合金放電容易。

關鍵字

高熵儲氫合金CrFeMnTiVZr ； AB2型C14 Laves相 ； 鎳氫電池 ； 放電容量 ； 循環壽命

並列摘要

The subject of this study is for AB2 C14 Laves CrFeMnTiVZr alloy. By modulating the individual elements, tens of alloys with both non-equal and equal molar contents, including a 7-element CoCrFeMnTiVZr alloy, were designed. The aim of this study is to investigate the individual effect of each composed element on the discharge capacity and cycle life of nickel-metal hydride cell. Bulk alloys were arc-melted in a water-cooled Cu-mold in vacuum, crushed, 325-mesh screened, activated to eliminate the poisoned surface of the alloy particles, slurry blending with PTFE, and then compressed into a negative electrode. A counterpart, nickel oxyhydroxide positive electrode, was also made. Nickel-metal hydride cells were home-made with a negative electrode and a nickel oxyhydroxide positive electrode by use of 30 wt% KOH solution as electrolyte. An automatic charge-discharge system was used to record voltage, current, and time by setting the charge-discharge condition, and to calculate the discharge capacity and cycle life of the cells.
The alloy composition influences many important characteristics of cells such as the charge-discharge ability, thermodynamic properties, oxidation and corrosion resistance, micronization of particles, discharge kinetics, catalytic properties, the ability of hydrogen recombination, and cycle life. Preliminary results show that the best cell discharge is the Fe1.5 (CrFe1.5MnTiVZr) alloy, and its maximum discharge capacity reaches 143.34 mAh/g. Cell with best cycle life in this experiment is that of Mn0 (CrFeTiVZr) alloy with the 30-cycle discharge capacity remaining 50% of its maximum capacity. The cell made of 7-element CoCrFeMnTiVZr alloy has higher discharge ability than those of the 6-element equal and non-equal molar alloys have.

並列關鍵字

High-entropy CrFeMnTiVZr alloy ； AB2 C14 Laves phase ； nickel-metal hydride cell ； discharge capacity ； cycle life

參考文獻

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