Lithium Titanium Oxide Anode for Zero-Volt Storage
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Solution Overview
Problem
Conventional lithium-ion batteries with graphite anodes suffer from rapid irreversible capacity fade and increased internal resistance when stored or discharged near zero-volts, due to zero-volt crossing potential issues and safety concerns related to lithium dendrite growth, limiting their long-term deep discharge and storage capabilities.
Innovation Solution
The use of a lithium titanium oxide anode with a higher redox potential, coated with functional materials and encapsulated in a polymeric network, paired with a high voltage cathode like LiNi0.5Mn1.5O4, which maintains stability and prevents solid electrolyte interface film dissolution, enabling safe and efficient near zero-volt storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If graphite anode-based lithium-ion batteries are discharged or stored near zero-volts, then the battery can be deeply discharged to maximize energy utilization, but the anode and cathode potentials are crossed causing zero-volt crossing potential issues that lead to rapid irreversible capacity fade and increased internal resistance
Solution Approach 1:
The patent changes the anode material from graphite to lithium titanium oxide (LTO), which fundamentally alters the electrochemical parameters including redox potential and operating voltage range. This parameter change eliminates the zero-volt crossing potential issue by maintaining a stable potential above the copper current collector dissolution potential even during deep discharge
Solution Approach 2:
The patent employs composite material structures including LTO anode coated with functional materials (such as carbon coatings or conductive polymers) and encapsulated in polymeric networks. These composite structures enhance the inherent properties of LTO by improving conductivity, stabilizing the structure, and preventing solid electrolyte interface film dissolution
2Use of energy by moving object
If graphite anode-based lithium-ion batteries are discharged or stored near zero-volts, then deep discharge is achieved, but the discharge potential exceeds the copper current collector dissolution potential causing rapid capacity fade
Solution Approach 1:
By changing the anode material to LTO, the patent shifts the anode potential curve to remain above the copper dissolution potential throughout the entire discharge range. This parameter change allows deep discharge to proceed without triggering the harmful copper dissolution reaction that causes capacity fade in graphite-based batteries
3Power
If graphite anode-based lithium-ion batteries are charged at high rates or stored at low temperatures, then power delivery is improved, but lithium dendrite growth occurs on the graphite anode increasing safety risks
Solution Approach 1:
The patent changes the anode material from graphite to LTO, which has a higher operating potential and different electrochemical behavior. This parameter change eliminates the conditions that promote lithium dendrite formation on graphite, as LTO's higher potential and stable structure prevent dendrite nucleation and growth during high-rate charging or low-temperature operation
4Object-affected harmful factors
If lithium iron phosphate cathode with graphite anode is used, then the battery has benign safety characteristics due to strong covalent bonding preventing oxygen liberation, but the low redox potential limits the cell voltage to about 3.3V
Solution Approach 1:
The patent uses composite material strategies including LTO anode with functional coatings and polymeric network encapsulation to enable the use of higher voltage cathode materials. These composite structures provide stability and protection that allow operation at higher voltages while maintaining safety
Solution Approach 2:
The patent changes the anode material to LTO, which has a higher redox potential than graphite. This parameter change increases the voltage difference between cathode and anode, thereby increasing the cell voltage from 3.3V to higher values while maintaining safety through the inherent stability of LTO and the protective functional coatings
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
This configuration enhances the cycle life and storage life of lithium-ion batteries, preventing capacity fade and safety hazards, while allowing for high energy density, long-term deep discharge, and storage at near zero-volts, thus addressing the limitations of graphite anode-based batteries.
Implementation Method 1
The use of a lithium titanium oxide anode with a higher redox potential, coated with functional materials and encapsulated in a polymeric network
Implementation Method 2
Most lithium-ion batteries function through lithium ion intercalation and deintercalation
Implementation Method 3
the formation of a solid electrolyte interface film that is reductively formed on a lithiated graphite anode surface during battery formation cycles
Implementation Method 4
conventional lithium-ion battery electrolytes, consisting of a lithium salt dissolved in a carbonate solvent mixture
Data Source
AI summary
A high energy/power density, long cycle life and safe lithium ion cell capable of long-term deep discharge/storage near zero-volt is described. The cell utilizes a near zero-volt storage capable anode, such as a spinel Li4Ti5O12, coupled to a high voltage, high-energy and/or high-power density cathode, such as LiNi0.5Mn1.5O4. The near zero-volt storage cell is rechargeable and affords safety advantages for battery transportation, storage, and handling, and significant cost reductions for cell maintenance. The cells produce high-energy and/or high-power densities and long cycle life. The cell anode, cathode, and separator active materials are coated with one or more protection or stability enhancing and/or conductivity enhancing materials to enhance electrochemical performance and to strengthen stabilities for long-term cycle life and storage life.