Ultrafast Al³⁺ Conduction through Cooperative Bonding in Disordered Polycarbonate-Polyether Electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state aluminum-ion batteries offer high energy density but face challenges with current polymer electrolytes.
• Polyethylene oxide (PEO)-based electrolytes, while used in lithium-ion batteries, exhibit poor performance in aluminum-ion systems due to strong Al3+ coordination and high crystallinity.

Purpose of the Study:

• To develop a novel blended polymer electrolyte (BPE) for solid-state aluminum-ion batteries.
• To overcome limitations of PEO-based electrolytes, including poor ion dissociation, high crystallinity, and insufficient mechanical strength.

Main Methods:

• A blended polymer electrolyte (BPE) was synthesized using polypropylene carbonate (PPC) and polyethylene oxide (PEO).
• The structural and electrochemical properties of the BPE were investigated, including its effect on Al3+ mobility and mechanical strength.
• Al//Al symmetric cells and Al//BQPT cells were assembled to evaluate cycling stability and rate performance.

Main Results:

• The PPC/PEO blended polymer electrolyte disrupted PEO crystallization, creating amorphous channels that enhanced Al3+ mobility and ionic conductivity.
• The BPE exhibited a tensile strength of 672 kPa, effectively suppressing aluminum dendrite formation.
• Al//Al symmetric cells demonstrated stable cycling for 200 hours, and Al//BQPT cells retained 130 mAh g-1 after 120 cycles at 1 A g-1.

Conclusions:

• The developed blended polymer electrolyte offers a promising solution for high-safety solid-state aluminum-ion batteries.
• The unique dual-network structure and tailored Al3+ coordination of the BPE significantly improve electrochemical performance and stability.