Lithium-Rich Cathode Material Pre-Activation Process
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Solution Overview
Problem
Lithium ion secondary batteries using lithium-rich cathode active materials face challenges in achieving high initial efficiency and energy density due to the need for activation treatment, leading to excess anode active material and reduced energy density.
Innovation Solution
A process involving the mixing of a lithium compound, an alkali metal compound, and a transition metal-containing compound, followed by firing and subsequent removal of the alkali metal to produce a cathode active material with the formula aLi(Li1/3Mn2/3)O2·(1−a)LiMO2, which enhances the initial efficiency and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-rich cathode active material is used to increase discharge capacity, then the discharge capacity is improved, but the initial efficiency becomes low due to required activation treatment
Solution Approach 1:
The patent applies preliminary action by conducting activation treatment during the manufacturing process rather than requiring post-manufacturing activation. The cathode active material is pre-treated with lithium hydroxide solution to form a stable surface layer before battery assembly, so that the activation process occurs in advance during production. This eliminates the need for additional activation cycles that would otherwise consume capacity and reduce initial efficiency.
Solution Approach 2:
The patent uses lithium hydroxide solution as an intermediary substance to mediate between the cathode active material and the battery operating conditions. The lithium hydroxide treatment creates a stable surface layer that acts as an intermediary interface, preventing harmful reactions while enabling smooth lithium ion insertion/extraction. This intermediary layer resolves the contradiction by facilitating both high discharge capacity and high initial efficiency simultaneously.
2Quantity of substance
If activation treatment is conducted to enable lithium-rich cathode active material usage, then discharge capacity is improved, but excess anode active material is required reducing energy density
Solution Approach 1:
By performing activation treatment during manufacturing rather than requiring additional anode material to compensate for initial capacity loss, the patent eliminates the need for excess anode active material. The pre-treatment ensures that all cathode material is immediately可利用 for capacity, optimizing the mass ratio between cathode and anode materials and thereby maximizing energy density.
3Quantity of substance
If lithium-rich cathode active material is used, then high discharge capacity is achieved, but manufacturing complexity increases due to additional activation treatment requirements
Solution Approach 1:
The patent merges the activation treatment step with the existing manufacturing process by incorporating lithium hydroxide solution treatment into the standard production line. Instead of adding a separate, complex activation step after battery assembly, the treatment is integrated into the manufacturing flow, combining multiple functions into a unified process that reduces overall manufacturing complexity.
Solution Approach 2:
Lithium hydroxide solution serves as a simple intermediary that enables the transition from conventional to lithium-rich cathode materials without requiring complex equipment or processes. The treatment uses readily available lithium hydroxide solution and standard coating/drying equipment, avoiding the need for specialized activation facilities and simplifying the manufacturing workflow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process results in a lithium ion secondary battery with improved initial efficiency and reduced excess anode active material, achieving higher energy density by optimizing the cathode active material composition and structure.
Implementation Method 1
a step of firing the mixture at a temperature of from 900 to 1,100° C. to obtain a first lithium-containing composite oxide containing the alkali metal other than Li
Data Source
AI summary
To provide a process for producing a cathode active material capable of obtaining a lithium ion secondary battery which has a high discharge capacity and a high initial efficiency, a cathode active material, a positive electrode for a lithium ion secondary battery, and a lithium ion secondary battery. A process for producing a cathode active material, which comprises a mixing step of mixing a lithium compound, an alkali metal compound other than Li, and a transition metal-containing compound containing at least Ni and Mn to obtain a mixture, a step of firing the mixture at a temperature of from 900 to 1,100° C. to obtain a first lithium-containing composite oxide containing the alkali metal other than Li, and a step of removing the alkali metal other than Li from the first lithium-containing composite oxide to obtain a second lithium-containing composite oxide represented by the following formula:aLi(Li1/3Mn2/3)O2·(1−a)LiMO2 wherein 0<a<1, and M is an element containing at least Ni and Mn.