Secondary lithium battery using a new layered anode material

Abstract

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.

Dependencies are inferred from the claim text.