Noh Jung Pil, Jung Ki Taek, Cho Gyu Bong, Lee Sang Hun, Kim Ki Won, Nam Tae Hyun
School of Materials Science and Engineering, Gyeongsang National University, 501, Jinju-Daero, Jinju, Gyeongnam 660-701, Korea.
J Nanosci Nanotechnol. 2012 Jul;12(7):5937-41. doi: 10.1166/jnn.2012.6399.
LiCoO2 thin films were fabricated by direct current magnetron sputtering method on STS304 and Ti substrates. The effects of substrate and annealing on their structural and electrochemical properties of LiCoO2 thin film cathode were studied. Crystal structures and surface morphologies of the deposited films were investigated by X-ray diffraction and field emission scanning electron microscopy. The as-deposited films on both substrates have amorphous structure. The (104) oriented perfect crystallization was obtained by annealing over 600 degrees C in STS304 substrate. The LiCoO2 thin film deposited on Ti substrate shows the (003) texture after annealing at 700 degrees C. The electrochemical properties were investigated by the cyclic voltammetry and charge-discharge measurement. The 600 degrees C-annealed LiCoO2 film deposited on STS304 substrate exhibits the inithial discharge capacity of 22 uAh/cm2 and the 96% capacity retention rate at 50th cycles. The electrochemical measurement on annealed films over 600 degrees C was impossible due to the formed TiO2 insulator layer using Ti substrate. As a result, it was found that the STS304 substrate seems to be more suitable material than the Ti substrate in fabricating LiCoO2 thin film cathode.
采用直流磁控溅射法在STS304和钛基板上制备了LiCoO₂薄膜。研究了基板和退火对LiCoO₂薄膜阴极结构和电化学性能的影响。通过X射线衍射和场发射扫描电子显微镜研究了沉积薄膜的晶体结构和表面形貌。两种基板上的沉积薄膜均具有非晶结构。在STS304基板上600℃以上退火可获得(104)取向的完美结晶。沉积在钛基板上的LiCoO₂薄膜在700℃退火后呈现(003)织构。通过循环伏安法和充放电测量研究了电化学性能。沉积在STS304基板上经600℃退火的LiCoO₂薄膜的初始放电容量为22 μAh/cm²，在第50次循环时容量保持率为96%。由于使用钛基板形成了TiO₂绝缘层，因此无法对600℃以上退火的薄膜进行电化学测量。结果发现，在制备LiCoO₂薄膜阴极方面，STS304基板似乎比钛基板更适合。
