CATHODE ACTIVE MATERIAL AND LITHIUM-ION BATTERY

Smart overview of the Invention

Cathode Active Material Composition: The cathode active material in this patent is designed for lithium-ion batteries. It consists of crystalline primary particles that include lithium (Li), nickel (Ni), manganese (Mn), and oxygen (O). These particles form a single-crystal active material with a crystal structure belonging to the space group R-3m. When analyzed with a transmission electron microscope, these particles display a first exposed surface that is not a (003) plane, with a specific Mn distribution ratio between the surface and the bulk regions defined as X and Y, respectively, satisfying the condition 1.1≤X/Y.

Innovative Mn Distribution: The unique aspect of this material is its Mn distribution. The Mn amount on the exposed surface other than the (003) plane is higher than that in the bulk region. This specific distribution is crucial for enhancing the battery's capacity retention over repeated charge and discharge cycles. The patent suggests that increasing Mn on these surfaces, as opposed to Ni, stabilizes the crystal planes crucial for lithium ion insertion and extraction, thereby improving the battery's performance.

Structural Characteristics: The primary particles have a main phase crystal structure that gives the highest-intensity peak in X-ray diffraction measurements. They also exhibit a second exposed surface of the (003) plane. The Mn distribution on this plane is defined by parameters P and Q, maintaining a ratio of 0.95≤P/Q≤1.05. These structural characteristics are designed to optimize the battery's discharge capacity and capacity retention.

Particle Size and Composition: The patent specifies that the average size of the primary particles should be at least 0.5 μm. The composition of these particles is described by a formula LixNiaCobMncOy, with constraints on the proportions of each element to ensure the desired performance. The constraints are 0.1≤x≤1.5, 0.5≤a≤1.0, 0≤b≤0.3, 0

Application in Lithium-Ion Batteries: This cathode active material is intended for use in lithium-ion batteries, which include a cathode active material layer, an anode active material layer, and an electrolyte layer between them. The material's design aims to enhance the capacity retention of the battery, making it suitable for applications requiring long-lasting and efficient energy storage, such as in electric vehicles.