Effects of Washing and Heat-treatment on Structure and Electrochemical Charge/Discharge Property for LiNi$lt;inf$gt;0.8$lt;/inf$gt;Co$lt;inf$gt;0.15$lt;/inf$gt;Al$lt;inf$gt;0.05$lt;/inf$gt;O$lt;inf$gt;2$lt;/inf$gt; Powder