Liquid-Zinc Flow Battery Anode for Dendrite-Free High Areal Capacity

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Solution Overview

Problem

Zinc-based flow batteries are limited by low areal capacity and dendrite formation, which restricts their energy density and lifespan, failing to meet the requirements of high-energy and long-lasting applications.

Innovation Solution

A dendrite-free zinc-based flow battery design incorporating a liquid-liquid electrode-electrolyte interface with gallium-based liquid metal alloys, allowing for high areal capacity and self-healing properties to prevent dendrite growth, featuring a novel liquid-zinc anode and eutectic alloys that facilitate alloying/dealloying reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If zinc deposition/dissolution reactions are used in conventional Zn-FBs, then the battery operates with solid electrodes, but the areal capacity is constrained and dendrite formation occurs

Engineering Contradiction:

Improveareal capacityVSAvoiddendrite formation

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention changes the physical state parameter of zinc from solid to liquid by using a eutectic alloy system (Zn-In-Ga-Sn) with melting point below room temperature. This parameter change enables zinc to exist as a liquid metal anode, fundamentally altering the deposition/dissolution mechanism and eliminating dendrite formation while achieving ultra-high areal capacity of 640 mAh cm−2

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite liquid metal alloy system comprising Zn, In, Ga, and Sn elements. This composite material approach creates a eutectic alloy with unique properties: liquid state at room temperature, high zinc solubility, and inherent dendrite-suppressing characteristics. The composite nature of the alloy allows simultaneous achievement of high areal capacity and dendrite-free operation

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If the areal capacity of deposited zinc is increased to enhance energy density, then the energy density improves, but dendrite formation is exacerbated and lifespan is reduced

Engineering Contradiction:

Improveenergy densityVSAvoidlifespan

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

By changing zinc from solid to liquid state through eutectic alloy composition, the invention enables ultra-high areal capacity (640 mAh cm−2) without the dendrite formation that normally limits both energy density and lifespan. The liquid state allows uniform zinc distribution and reversible alloying/dealloying reactions, achieving both high energy density and long cycle life simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the typically harmful dendrite formation mechanism into a beneficial uniform alloying process. Instead of zinc depositing as dendritic structures on solid electrodes, zinc atoms dissolve uniformly into the liquid eutectic alloy, creating a homogeneous liquid metal anode that eliminates the harm of dendrites while maximizing energy density

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 battery achieves an areal capacity of at least 600 mAh cm−2 at 40 mA cm−2 current density with 95% coulombic efficiency and 84% energy efficiency, maintaining stable charging/discharging performance for over 4000 hours and cycle life exceeding 170 days.

Implementation Method 1

The charge/discharge of the anode corresponds to alloying/dealloying reactions of zinc in LM

Methodology Applied

Scientific EffectAlloying/dealloying reactions:

Implementation Method 2

The deposition/dissolution of Zn2+/Zn pair also corresponds to alloying/dealloying reaction of zinc in LM. The liquid-Zn anode can be flowed out of the Zn-FBs, obtaining ultra-high areal capacity without dendrite formation

Methodology Applied

Scientific EffectLiquid-liquid phase transition: Phase Change

Implementation Method 3

a first pump connects the cathode and the first storage tank, a second pump connects the anode and the second storage tank

Methodology Applied

Scientific EffectPumping: Pump

Implementation Method 4

a separator to prevent direct contact between the anolyte and the catholyte

Methodology Applied

Scientific EffectPhysical separation: Physical Containment

Implementation Method 5

Aqueous redox flow batteries (ARFBs) represent a significant technology within the realm of energy storage

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS20250336990A1Dendrite-free zinc-based flow battery with high areal capacity

Publication Date: 2025.10.30 CITY UNIVERSITY OF HONG KONG

AI summary

The present invention provides a dendrite-free zinc-based flow battery. The flow battery includes an anode integrated with a first collector, a cathode integrated with a second collector, a first storage tank comprising catholyte, a first pump connects the cathode and the first storage tank, a second storage tank comprising anolyte and liquid eutectic alloys, a second pump connects the anode and the second storage tank, and a separator to prevent direct contact between the anolyte and the catholyte. The room-temperature gallium-based liquid metals (Ga-LM) alloys enable zinc-based flow batteries (Zn-FBs) to achieve unparalleled areal capacity and exceptionally long cycle life.