Constructing hyperbranched polymers as a stable elastic framework for copper sulfide nanoplates for enhancing...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are promising for large-scale energy storage.
• High-capacity anode materials with good cyclability and coulombic efficiency are crucial for SIBs.
• Electrochemical conversion reactions offer potential for high-capacity anodes but face challenges in stability and efficiency.

Purpose of the Study:

• To develop a high-performance anode material for SIBs using electrochemical conversion reactions.
• To address the challenges of poor long-term cyclability and low first-cycle coulombic efficiency in SIB anodes.
• To demonstrate a novel templating strategy for constructing advanced electrode materials.

Main Methods:

• Synthesis of hierarchical Cu9S5 nanoplates using a hyperbranched polymer as a template and additive.
• Morphological and microstructural characterization of the synthesized Cu9S5 composite.
• Electrochemical testing of the Cu9S5 composite as an anode in SIBs, including capacity, rate capability, and cycling stability measurements.
• Kinetic studies to evaluate charge transfer resistance and Na+ ion diffusion.

Main Results:

• The Cu9S5 composite anode achieved a high reversible capacity of 429 mA h g-1 at 100 mA g-1.
• An excellent first-cycle coulombic efficiency of 94.3% was recorded.
• Superior rate capability (300 mA h g-1 at 20 A g-1) and outstanding cyclability (82.2% retention after 1000 cycles) were observed.
• Low charge transfer resistance and a high Na+ diffusion coefficient (∼10-9 cm2 s-1) were determined.

Conclusions:

• The novel hyperbranched polymer-templated Cu9S5 nanoplates represent a promising anode material for high-performance SIBs.
• The templating strategy effectively regulates morphology, enhances ion diffusion, and alleviates aggregation, leading to improved electrochemical performance.
• This work presents a viable approach for designing advanced conversion materials for next-generation sodium-ion batteries.