Positive electrode active material for lithium ion battery, method of producing the same, electrode for lithium ion battery, and lithium ion battery

Abstract

Provided is a positive electrode active material for lithium ion batteries, which is capable of realizing stability and safety at a high voltage, a high energy density, high load characteristics, and long-term cycle characteristics by controlling a crystal shape of LiMnPO 4 particles having a crystal structure very suitable for Li diffusion or controlling an average primary particle size, a production method thereof, an electrode for lithium ion batteries, and a lithium ion battery. The positive electrode active material for lithium ion batteries of the invention is a positive electrode active material for lithium ion batteries, which is formed from LiMnPO 4 . Values of lattice constants a, b, and c, which are calculated from an X-ray diffraction pattern, satisfy 10.41 Å<a≦10.43 Å, 6.070 Å<b≦6.095 Å, and 4.730 Å<C≦4.745 Å, and an average particle size is 10 to 100 nm.

1 - 5 . (canceled) 
     
     
         6 . A positive electrode active material for lithium ion batteries, which is formed from LiMnPO 4  particles,
 wherein values of lattice constants a, b, and c, which are calculated from an X-ray diffraction pattern of the LiMnPO 4  particles, satisfy 10.41 Å<a≦10.43 Å, 6.070 Å<b≦6.088 Å, and 4.730 Å<c≦4.745 Å; and   an average particle diameter of the LiMnPO 4  particles is 10 to 100 nm.   
     
     
         7 . A method of producing a positive electrode active material for lithium ion batteries, which is formed from LiMnPO 4  particles, by a hydrothermal synthesis method, the method comprising:
 a step of heating raw material slurry obtained by mixing a Li source, a P source, and a Mn source with a solvent containing water as a main component to a temperature within a range of 100 to 150° C., and performing synthesis under compression,   wherein values of lattice constants a, b, and c, which are calculated from an X-ray diffraction pattern of the LiMnPO 4  particles, satisfy 10.41 Å<a≦10.43 Å, 6.070 Å<b≦6.088 Å, and 4.730 Å<c≦4.745 Å; and   an average particle diameter of the LiMnPO 4  particles is 10 to 100 nm.   
     
     
         8 . An electrode for lithium ion batteries, containing:
 the positive electrode active material for lithium ion batteries according to  claim 6 .   
     
     
         9 . A lithium ion battery, comprising:
 the electrode for lithium ion batteries according to  claim 8 .   
     
     
         10 . The positive electrode active material for lithium ion batteries according to  claim 6 ,
 wherein an average particle diameter of the LiMnPO 4  particles is 15 to 60 nm.   
     
     
         11 . The positive electrode active material for lithium ion batteries according to  claim 6 , wherein the LiMnPO 4  particles are obtained by a hydrothermal synthesis method, the method comprising:
 a step of heating raw material slurry obtained by mixing a Li source, a P source, and a Mn source with a solvent containing water as a main component to a temperature within a range of 100 to 150° C., and performing synthesis under compression.   
     
     
         12 . The positive electrode active material for lithium ion batteries according to  claim 6 , wherein the LiMnPO 4  particles are obtained by a hydrothermal synthesis method, the method comprising:
 a step of heating raw material slurry obtained by mixing a Li source, a P source, and a Mn source with a solvent containing water as a main component to a temperature within a range of 100 to 150° C., and performing synthesis under compression for 1 to 48 hours.   
     
     
         13 . The positive electrode active material for lithium ion batteries according to  claim 6 , wherein the raw material slurry includes the Li source, the P source, and the Mn source at a molar ratio of 3:1:1. 
     
     
         14 . The positive electrode active material for lithium ion batteries according to  claim 6 , wherein the synthesis is performed at a pressure of 0.1 to 0.7 MPa. 
     
     
         15 . The method of producing a positive electrode active material for lithium ion batteries according to  claim 7 , wherein the raw material slurry includes the Li source, the P source, and the Mn source at a molar ratio of 3:1:1. 
     
     
         16 . The method of producing a positive electrode active material for lithium ion batteries according to  claim 7 , wherein the synthesis is performed under compression for 1 to 48 hours. 
     
     
         17 . The method of producing a positive electrode active material for lithium ion batteries according to  claim 7 , wherein the synthesis is performed at a pressure of 0.1 to 0.7 MPa.