Crystalline nanometric LiFePO4

Patent metadata

Field	Value
Publication number	US-9954227-B2
Application number	US-99392506-A
Country	US
Kind code	B2
Filing date	Jun 15, 2006
Priority date	Jun 29, 2005
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

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 LiFePO 4 powders with enhanced electrochemical properties. A direct precipitation process is described for preparing crystalline LiFePO 4 powder, 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 distribution within the battery.

First claim

The invention claimed is:

1. A carbon-free crystalline LiFePO 4 powder having a particle size distribution with an average particle size d50 below 200 nm, wherein the particle size distribution ratio (d90−d10)/d50 is less than 0.8 and wherein the maximum particle size is below 500 nm.

2. The carbon-free crystalline LiFePO 4 powder according to claim 1 , wherein the average particle size d50 is below 200 nm and above 50 nm.

3. The carbon-free crystalline LiFePO 4 powder according to claim 1 , wherein the particle size distribution is mono-modal and the ratio (d90−d10)/d50 is less than 0.65.

4. The carbon-free crystalline LiFePO 4 powder according to claim 1 , wherein the particle size distribution is mono-modal and the ratio (d90−d10)/d50 is less than 0.5.

Assignees

• Delacourt Charles
• Poizot Philippe
• Masquelier Christian
• Umicore Nv

Inventors

• Delacourt Charles
• Poizot Philippe
• Masquelier Christian

Classifications

• H01M10/0565

  Polymeric materials, e.g. gel-type or solid-type · CPC title

• C01B25/37 Primary

  Phosphates of heavy metals · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• Y10T428/2982

  Particulate matter [e.g., sphere, flake, etc.] · CPC title