Patent ID: 6316144
Filing Date: 2001-11-13
Classification: H01M,Y02E

Abstract:
A carbonaceous insertion compound comprising:(a) a pre-graphitic carbonaceous host having a reversible capacity for lithium insertion, an irreversible capacity for lithium insertion, and a surface area accessible to a non-aqueous electrolyte wherein(i) the empirical parameter R for said carbonaceous insertion compound:(A) is, determined by X-ray diffraction using a diffractometer equipped with a copper target X-ray tube and a diffracted beam monochronometer, with the X-ray beam of said diffractometer being confined to the sample in the angular range from 10.degree. to 35.degree. in scattering angle,(B) is defined as the height of the centre of the {002} peak divided by the background level, and(C) is less than about 2.2;(ii) the H/C atomic ratio is less than about 0.1; and(iii) the electrolyte accessible surface area is sufficiently small such that the irreversible capacity is less than about a half that of the reversible capacity;(b) and alkali metal atoms reversibly inserted into the carbonaceous host in an amount greater than that which can be reversibly inserted into graphite.