Crystalline nanometric LiFePO4
US9954227B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 2006 |
| Grant date | Apr 24, 2018 |
| Priority date | — |
| Expiry date | Mar 25, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2982
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention relates to lithium secondary batteries and more specifically to positive electrode materials operating at potentials greater than 2.8 V vs. Li+/Li in nonaqueous electrochemical cells. In particular, the invention relates to crystalline nanometric carbon-free olivine-type LiFePO4 powders with enhanced electrochemical properties. A direct precipitation process is described for preparing crystalline LiFePO4powder, comprising the steps of: —providing a water-based mixture having at a pH between 6 and 10, containing a water-miscible boiling point elevation additive, and Li(I), Fe(II) and P(V) as precursor components; —heating said water-based mixture to a temperature less than or equal to its boiling point at atmospheric pressure, thereby precipitating crystalline LiFePO4 powder. An extremely fine 50 to 200 nm particle size is obtained, with a narrow distribution. The fine particle size accounts for excellent high-drain properties without applying any carbon coating. This allows for a significant increase in the active material content of the electrode. The narrow distribution facilitates the electrode manufacturing process and ensures a homogeneous current distrib…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.