Lithium Anode Dendrite Healing via Self-Heating
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Solution Overview
Problem
The growth of lithium dendrites during electrochemical plating and stripping in Li-ion batteries leads to irreversible capacity loss, reduced coulombic efficiency, electrolyte degradation, and safety hazards like thermal runaway and electrical shorting, limiting the energy density and service life of these batteries.
Innovation Solution
Operating energy storage devices at a healing current density higher than the standard operating current density to generate heat, which smoothes out dendrites on the anode surface, thereby prolonging the service life by fusing adjacent dendrites and preventing electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Li metal anodes are used to achieve ultra-high theoretical specific capacity, then energy density is improved, but dendritic growth occurs leading to safety hazards and reduced service life
Solution Approach 1:
The patent applies periodic action by implementing a dual-mode charging protocol that alternates between standard charging mode and healing mode. The healing mode is activated periodically during charging to suppress dendrite formation, while standard mode provides normal capacity utilization. This periodic switching between operational states resolves the contradiction by maintaining anode reliability without sacrificing energy density.
2Reliability
If healing current density is increased to smooth dendrites, then service life is improved, but energy consumption increases
Solution Approach 1:
The patent applies partial action by implementing healing current density only during specific charging intervals rather than continuously. The healing mode operates at elevated current density (excessive action) but only for portions of the charging cycle, specifically when dendrite suppression is most critical. This partial application of excessive current resolves the contradiction by extending service life while minimizing additional energy consumption.
3Reliability
If dendritic growth is suppressed to prevent safety hazards, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies feedback by implementing a charging protocol that monitors charging progress and automatically switches between standard and healing modes based on state-of-charge thresholds. The system provides feedback to the control algorithm regarding anode conditions and charging status, enabling dynamic adjustment of current density. This feedback mechanism resolves the contradiction by ensuring safety through dendrite suppression while maintaining relatively simple implementation through automated control.
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 method effectively prolongs the service life of energy storage devices by reducing dendrite-related failures, enabling the use of metallic anodes with higher energy capacities and lower electrochemical potentials, while maintaining safety by preventing thermal runaway.
Implementation Method 1
operating the energy storage device at a healing current density to generate heat
Data Source
AI summary
A method of prolonging service life of an energy storage device such as a lithium-ion battery includes temporarily operating the battery at an elevated current density. Cycling of lithium-ion batteries at regular current densities results in the generation of lithium-metal dendrites at the surface of the anode, particularly in batteries where the anode is lithium metal. The lithium metal dendrites pose a threat to damage other components of the battery, such as separators, as well as causing an electrical short. Operating the battery in bursts at the elevated current density results in self-heating at the anode surface that merges adjacent lithium-metal dendrites and an overall smoothing of the anode surface. This method is also applicable to other alkali-metal-based batteries and chemistries.