Gel Polymer Electrolyte for Anode-Free Lithium Battery Stability
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Solution Overview
Problem
Lithium batteries using carbon-based anode active materials face stability issues due to volume changes during charging and discharging, and lithium metal batteries suffer from side reactions and lithium dendrite growth leading to short circuits.
Innovation Solution
An anode-free lithium battery design with a gel polymer electrolyte containing a first polymer, first and second lithium salts, and organic solvents, which suppresses volume changes and reduces side reactions, and includes a modified solid electrolyte interphase layer to inhibit lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as anode active material to increase theoretical electrical capacity, then energy density is improved, but side reactions with electrolyte cause lifespan deterioration
Solution Approach 1:
A gel polymer electrolyte is introduced as an intermediary between the lithium metal anode and the liquid electrolyte. This gel polymer electrolyte forms a stable solid electrolyte interphase (SEI) layer that acts as a protective barrier, preventing direct contact and side reactions between the lithium metal and the liquid electrolyte, thereby improving lifespan while maintaining high energy density
Solution Approach 2:
The patent uses a composite gel polymer electrolyte system combining organic electrolyte components with polymer matrix (PVDF, PAN, or PMMA). This composite structure provides both the ionic conductivity needed for high energy density and the mechanical stability required to suppress lithium dendrite growth and improve cycle life
2Use of energy by moving object
If anode active material layer is removed to improve energy density, then volume is reduced, but lithium dendrites may precipitate causing short circuit
Solution Approach 1:
The gel polymer electrolyte serves as a protective intermediary layer between the cathode and the lithium metal anode. Its gel structure with appropriate viscosity and mechanical strength physically suppresses lithium dendrite formation and growth, preventing short circuits while enabling anode-free design for high energy density
Solution Approach 2:
The patent modifies the electrolyte parameters by using gel polymer electrolyte with specific viscosity ranges (0.1-10 Pa·s) and adding lithium salts (LiBF4, LiPF6, LiClO4) at controlled concentrations. These parameter changes create optimal conditions for uniform lithium deposition and dendrite suppression
3Stability of the object's composition
If carbon-based anode active material is used to ensure stability, then volume change is suppressed, but theoretical electric capacity is limited
Solution Approach 1:
The patent removes the carbon-based anode active material layer entirely and replaces it with pure lithium metal anode. By taking out the limiting carbon layer and using lithium metal directly with gel polymer electrolyte, the system achieves both high capacity (3,860 mAh/g) and stability through the protective gel electrolyte interface
Solution Approach 2:
The invention changes the fundamental parameter of anode material from carbon-based compounds to pure lithium metal, fundamentally altering the capacity parameter from ~372 mAh/g to 3,860 mAh/g while using gel polymer electrolyte to maintain stability
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 gel polymer electrolyte enhances ionic conductivity and mechanical properties, improving the battery's cycle characteristics and preventing internal short circuits, thereby increasing energy density and lifespan.
Implementation Method 1
an electrolyte layer arranged between the cathode and the anode current collector, wherein the electrolyte layer includes a gel polymer electrolyte
Implementation Method 2
a novel (e.g., new) gel polymer electrolyte with excellent or suitable ionic conductivity is provided
Implementation Method 3
to suppress or reduce side reactions between an electrolyte and a lithium metal layer during a charging or discharging process of a lithium battery
Implementation Method 4
a modified solid electrolyte interphase layer to inhibit lithium dendrite growth
Data Source
AI summary
A lithium battery including a cathode, an anode current collector, and an electrolyte layer disposed between the cathode and the anode current collector is provided. The electrolyte layer includes a gel polymer electrolyte, wherein the gel polymer electrolyte includes a first polymer, a first lithium salt, a second lithium salt, a first organic solvent, and a second organic solvent, the first polymer includes a repeating unit derived from a first crosslinking monomer including three or more reactive functional groups, and the first lithium salt and the second lithium salt each independently include a borate-based lithium salt.