氧化釩/氮氧化釩混碳複合材料於鋰離子全電池之負極應用

Abstract

在眾多的電池能源技術中，鋰離子電池有高能量密度的特性，因此被廣泛的研究，近年來已成為電動車及消費性電子產品之主要儲能系統。三氧化二釩具有高的理論電容量 (1073 mAh g-1) 且地球含量豐富、低毒性，對環境較為友善，被視為鋰離子電池有潛力的陽極材料之一。除此之外，氮化釩有低電阻之特點也能有效提升電化學表現。在本研究中，我們利用簡易的水熱法製備五氧化二釩奈米線，接著利用氮化系統在氨氣環境下得到氧化釩/氮氧化釩之複合材料，可藉由控制不同氮化溫度得到不同氧化釩/氮氧化釩之比例，在製備極片的過程中，我們也加入導電碳黑來提升其循環壽命與電化學表現。當應用在鋰離子半電池時，氧化釩/氮氧化釩混碳的複合材料在80 mA g-1 的充放電速率下經過50次循環充放電後，電容值為357 mAh g-1。最重要的是我們成功將此複合陽極材料搭配商業化鋰鈷組成全電池，在41.4 mA g-1的充放電速率下經過50次循環充放電後，電容值為78 mAh g-1，除此之外，我們也使用高電壓正極材料鋰鎳錳氧組成全電池，在22.2 mA g-1的充放電速率下經過30次循環充放電後，電容值為45 mAh g-1，結果顯示此複合材料是有潛力作為鋰離子電池陽極材料之應用。

In this study, we present a facile preparation of vanadium oxide and vanadium oxynitride carbon composite as the anode materials for the full lithium ion Batteries. Vanadium trioxide (V2O3) are a promising anode materials for lithium ion batteries due to their high theoretical capacity (1070 mAh g-1), low toxicity and the numerous natural abundance. Furthermore, vanadium nitride also have chance to improve capacity performance and rate capability of the lithium ion batteries because of their low electrical resistivity. Here, we synthesized a vanadium oxide and vanadium oxynitride carbon nanoporous composite (V2O3/VOxNy-C) via a facile hydrothermal method and a nitridation process. In order to improve the cycling performance, we added Super P® (conductive carbon) to as-prepare vanadium oxide and vanadium oxynitride carbon nanoporous composite. They were directly used as the anode electrode in the lithium ion batteries without the process of slurry mixing. As a result, a V2O3/VOxNy-C//Li half cell delivered 357 mAh g-1 for 50 cycles at a current density of 80 mA g-1. Remarkably, the full lithium ion battery was assembled successfully. The full cells were assembled by using the V2O3/VOxNy-C composites and commercial LiCoO2, served as the anode and the cathode, respectively. The V2O3/VOxNy-C// LiCoO2 delivered a capacity of 78 mAh g-1 for 50 cycles at a current density of 41.1 mA g-1 (0.15 C), which shows a good electrochemical performance. We also used high cathode materials LiNi0.5Mn1.5O4 for full cell. The V2O3/VOxNy-C// LiNi0.5Mn1.5O4 shows a capacity of 45 mAh g-1 for 30 cycles at a current density of 22.2 mA g-1 (0.15 C). It indicates these composites material show the huge potential as the anode for lithium ion batteries.