Temperature-Dependent Li Storage Performance in Nanoporous Cu-Ge-Al Alloy

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-ion batteries (LIBs) face performance degradation and safety issues at low temperatures, limiting their use in cold environments.
• Alloy-type electrodes offer potential for stable, dendrite-free anodes at low temperatures.
• Developing robust anode materials is crucial for expanding LIB applications in diverse climatic conditions.

Purpose of the Study:

• To investigate the temperature-dependent lithium storage performance of aluminum-based nanoporous alloy anodes.
• To design and synthesize novel nanoporous copper-germanium-aluminum (Cu-Ge-Al) ternary alloys for enhanced low-temperature LIB applications.
• To understand the structural and electrochemical properties influencing anode performance at varying temperatures.

Main Methods:

• Synthesis of nanoporous Cu-Ge-Al alloys (NP-CuGeAl) via selective aluminum etching.
• Characterization of alloy composition, structure, and porosity (e.g., high-Al-content CGA-6, low-Al-content CGA-48).
• Electrochemical testing of anode performance at room temperature and low temperatures (-20 °C), including cycling stability and capacity retention.
• In situ transmission electron microscopy (TEM) and ex situ analyses to study charge-discharge mechanisms and structural evolution.

Main Results:

• The high-Al-content CGA-6 anode demonstrated excellent room-temperature performance with a capacity of 479.7 mAh g⁻¹ over 1020 cycles at 0.5 A g⁻¹.
• Low-aluminum-content alloys, specifically CGA-48, exhibited significantly improved electrochemical performance at -20 °C compared to CGA-6.
• In situ and ex situ studies confirmed the high reversibility of the intermetallic compound/lithiated intermetallic compound couples and the structural integrity of the porous architecture during cycling.

Conclusions:

• Aluminum-based nanoporous alloys are effective anode materials for LIBs, particularly at low temperatures.
• The composition and porous structure of Cu-Ge-Al alloys can be tuned to optimize performance across different temperature ranges.
• These findings pave the way for developing reliable LIBs for applications in cold climates.