An improved lithium secondary battery using a novel layered titanium phosphate having the formula of TiO(OH)(H.sub.2 PO.sub.4), or LTP, as anode material, and LiCoO.sub.2, LiNiO.sub.2, or other appropriate material, as cathode. A stable operating voltage of 3-volt can be obtained from the resultant lithium secondary battery. The layered titanium phosphate is prepared by first reacting a tetramethylammonium hydroxide (N(CH.sub.3).sub.4 OH) solution containing orthophosphoric acid with titanium dioxide in a low temperature hydrothermal reaction to form a tetramethylammonium form of layered titanium phosphate, or NMe.sub.4 TP, which serves as the precursor of LTP. The precursor NMe.sub.4 TP is then placed in a concentrated hydrochloric acid at room temperature to obtain a high purity LTP via a cation exchange reaction. Each of the Li.sub.x LTP chemical unit, which is formed after the intercalation of LTP with lithium ions, can contain two lithium ions, thus excellent lithium intercalation characteristic can be achieved as a result. Furthermore, no lithium dendrites are formed during the recharging operation which tend to puncture the partition membranae separating the anode and the cathode; therefore, the secondary lithium battery allows a safe recharging operation to be maintained.
一种改进的
锂二次电池,使用一种新型层状
钛磷酸盐(LTP),其
化学式为TiO(OH)(H.sub.2 PO.sub.4)作为阳极材料,LiCoO.sub.2,LiNiO.sub.2或其他适当的材料作为阴极。由此产生的
锂二次电池可以获得稳定的3伏特工作电压。层状
钛磷酸盐是通过首先将含有正
磷酸的
四甲基氢氧化铵(N(CH.sub.3).sub.4 OH)溶液与
二氧化钛在低温
水热反应中反应形成
四甲基铵型层状
钛磷酸盐或NMe.sub.4 TP,其作为LTP的前体。然后将前体NMe.sub.4 TP置于室温下的浓
盐酸中,通过阳离子交换反应获得高纯度的LTP。每个Li.sub.x LTP
化学单元,在LTP与
锂离子插层后形成,可以含有两个
锂离子,因此可以实现优异的
锂插层特性。此外,在充电操作期间不会形成
锂树枝,这些树枝倾向于刺穿隔膜将阳极和阴极分开;因此,二次
锂电池可以保持安全的充电操作。