氧化釩/氮氧化釩混碳的複合材料之簡易合成及其在鋰離子電池之應用

Abstract

在眾多能源技術課題中，因為鋰離子電池有高能量密度，因此一向為熱門的研究。由於三氧化二釩具有高理論電容量 (1073 mAh g-1)、地球含量高及低毒性，因此被視為有潛力的陽極材料。除了三氧化二釩，氮化釩低電阻之特性也能夠有效提升電化學效能。在本研究中，我們利用水熱法及過濾步驟製成五氧化二釩的自支撐薄膜，接著利用氮化法得到氧化釩/氮氧化釩之複合材料，可以經由控制氮化溫度改變氧化釩/氮氧化釩比例，且此薄膜可以直接作為鋰電的電極材料不須額外混漿塗膜致電流收集板。在製備電極之過程中，我們也加入導電碳黑來提升循環效能。當應用於鋰離子電池之陽極，氧化釩/氮氧化釩薄膜在100 mA g-1的充放電速度下經過50次循環充放電後有222 mAh g-1，氧化釩/氮氧化釩混碳之複合材料在80 mA g-1則有322 mAh g-1，結果顯示此複合材料是有潛力做為鋰離子電池之陽極材料。

Among the various battery technologies, lithium ion batteries stand out because of the facilitating design of storage systems with high energy density. To advance its performance, vanadium trioxide (V2O3) has been regarded as a potential anode material because of their high theoretical lithium storage capability (1073 mAh g-1), large nature abundance and low toxicity. In addition of V2O3, vanadium nitride also has the opportunity to improve performance due to its relatively low electrical resistivity. Herein, a simple process to prepare the electrode is introduced. Vanadium pentoxide nanowires are simply synthesized by hydrothermal method and compress into free-standing sheet. It is then transformed into vanadium oxide/vanadium oxynitride nanoporous composite (V2O3/VOxNy) by nitrodation process under NH3. Different vanadium oxide/vanadium oxynitride ratios were achieved by controlling the nitridation temperature. The free-standing (V2O3/VOxNy) sheet was direct used as anode electrode without the process of coating material with mixing slurry on the substrate. To improve cycling performance, we add Super P® (conductive carbon) to prepare vanadium oxide/vanadium oxynitride composite with Super P® (V2O3/VOxNy-C). As a result, V2O3/VOxNy and V2O3/VOxNy-C deliver 222 and 322 mAh g-1 up to fifty cycles at a current density of 100 and 80 mAh g-1. Thus, these composite films are promising candidates for anode of lithium-ion battery.