Surface preparation of natural graphite and the effect of impurities on grinding and the particle distribution
US7993621B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2007 |
| Grant date | Aug 9, 2011 |
| Priority date | — |
| Expiry date | Oct 24, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention relates to the physical or chemical specific purification of natural mineral graphite. This purification is preferably applied to the surface of natural graphite in order to allow the formation of a passivation film during the first electrical discharge or the insertion of lithium in the graphite when the latter is used in a lithium-ion cell. The grinding to a small size before purification allows the optimization of the distribution of the particles, resulting in a more uniform electrode. This grinding is carried out in the presence of the natural impurities of the graphite that play the role of a micro-abrasive and result in a hardness of the graphite that increases its mechanical properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.