Titanium-Doped LiMnFePO4 Cathode for High-Voltage Battery Life
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density, high operating voltage, improved low-temperature characteristics, and long lifespan.
Innovation Solution
A positive electrode active material comprising titanium-doped olivine-based lithium compounds with specific particle sizes and dopant concentrations is used, enhancing electrical conductivity and structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional positive electrode active materials are used, then manufacturing is simpler, but energy density and operating voltage are insufficient
Solution Approach 1:
The patent employs composite materials by combining multiple elements (Li, Mn, Fe, Ti, and dopants M) to form a complex olivine-based compound Li_aMn_xFe_(1-x)M_yPO_(4-b). This composite approach enables simultaneous achievement of high energy density, high operating voltage, and improved conductivity that single-element materials cannot provide alone.
Solution Approach 2:
The patent applies local quality through controlled doping where titanium is introduced at specific concentrations (1000-9000 ppm) and additional dopants M are added in controlled amounts (0 ≤ y ≤ 0.05). This localized modification of specific regions within the crystal structure enhances overall performance without requiring complete material replacement.
2Use of energy by moving object
If higher operating voltage is achieved, then energy density improves, but low-temperature characteristics deteriorate
Solution Approach 1:
The patent utilizes parameter changes by systematically varying the stoichiometric ratios (0.8 ≤ a ≤ 1.2, 0.2 ≤ x ≤ 0.8) and dopant concentrations to optimize the balance between operating voltage and low-temperature performance. The specific composition ranges are determined to achieve both high voltage operation and maintained conductivity at low temperatures.
Solution Approach 2:
The patent applies local quality through selective doping with titanium and additional dopants M at controlled concentrations, which locally modify the crystal structure to enhance electron conductivity without compromising the overall high operating voltage characteristics of the olivine-based material.
3Reliability
If titanium doping is increased to improve conductivity, then electrical conductivity improves, but structural stability may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling titanium content within the range of 1000-9000 ppm and limiting additional dopant M to 0 ≤ y ≤ 0.05. This controlled variation optimizes electrical conductivity while preventing excessive doping that would compromise the structural stability of the olivine framework.
Solution Approach 2:
The patent uses local quality by introducing titanium as a dopant at specific concentrations rather than uniformly replacing all metal ions. This localized substitution enhances conductivity at optimal levels while preserving the overall structural integrity of the LiMnFePO4 olivine structure.
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 solution results in a rechargeable lithium battery with improved energy density, operating voltage, low-temperature performance, and extended lifespan.
Implementation Method 1
A positive electrode active material including a first particle including titanium (Ti) in an amount (of Ti in the first particle) from about 1000 ppm to about 9000 ppm
Implementation Method 2
a positive electrode and a negative electrode each containing an active material capable of intercalation and deintercalation of lithium ions
Implementation Method 3
Electrical energy is produced by oxidation and reduction reactions when the lithium ions are intercalated and deintercalated into/from the positive electrode and the negative electrode
Data Source
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AI summary
A positive electrode active material for a rechargeable lithium battery, a positive electrode containing the same, and a rechargeable lithium battery including the same as provided. A positive electrode active material includes titanium (Ti) in an amount of about 1000 ppm to about 9000 ppm, at least one primary particle, the primary particle having a size of about 50 nm to about 300 nm, and a compound represented by Formula 1: Formula 1 LiaMnxFe1-xMyPO4-b wherein, in Formula 1 above, 0.8≤a≤1.2, 0.2≤x≤0.8, 0≤y≤0.05, 0≤b≤0.05, and M is at least one element selected from the group consisting of Al, Mg, Zr, V, Zn, Nb, K, Y, B, and Cu.