Particles containing a non-conducting or semi-conducting nucleus covered with a hybrid conducting layer, their processes of preparation and uses in electrochemical devices

Mixture of particles comprising a non-conducting or semi-conducting nucleus, the nuclei of said particles being at least partially covered with a hybrid conductor coating and said particles being at least partially connected through hybrid conducting chains which provide a network of electrical conductivity, wherein:

• the nucleus of said particles is at least 65% of one lithium oxide selected from the group consisting of oxides of the formula:
• Li4Ti5O12;
• Li(4-α)ZαTi5O12, in which 0<α≦0.33, Z represents a source of at least one metal;
• and
• Li4ZβTi(5-β)O12 in which 0<β≦0.5, Z represents at least one metal;
• each of the hybrid conductor coating and the hybrid conducting chains is a hybrid carbon mixture which comprises at least two different conducting forms of carbon, which are hereunder designated Carbon 1 and Carbon 2, wherein:
• Carbon 1 consists of particles with low crystallinity having a d002 greater than 3.36 Å if measured by X-ray diffraction or by Raman spectroscopy, said Carbon 1 possesses a specific surface area which, as measured by the BET method, is equal to or greater than 50 m2/g, and particles of Carbon 1 have an average size varying from 10 to 999 nm, and
• Carbon 2 consists of at least one of graphite particles and high crystallinity carbon particles with high crystallinity having a d002 smaller than 3.36 Å if measured by X-ray diffraction, particles of Carbon 2 have a specific surface area which, as measured by the BET method, is equal to or smaller than 50 m2/g, and the particles of Carbon 2 have a size varying from 2 to 10 μm,
• wherein the hybrid conductor coating comprises:
• a first, inner coating of Carbon 1 which covers between 50 and 90% of the surface of the nucleus, and
• a second, outer coating of Carbon 2.