Phase-Controllable Cobalt Phosphides Induced through Hydrogel for Higher Lithium Storages

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Transition metal phosphides (TMPs) are promising for energy storage but face challenges in synthesis and phase control.
• Current methods often use hazardous phosphorus sources and harsh conditions, limiting scalability and safety.

Purpose of the Study:

• To develop a novel, safe, and controllable method for synthesizing phase-controlled transition metal phosphides.
• To utilize functional hydrogels as precursors for creating advanced materials for energy storage applications.

Main Methods:

• Employed a semi-interpenetrating network (semi-IPN) hydrogel as a precursor for phase-controllable cobalt phosphide synthesis.
• Utilized poly(vinylphosphonic acid) (PVPA) within the hydrogel as a safe and stable phosphorus source.
• Extended the hydrogel templating method to synthesize other transition metal phosphides (Fe2P, Ni2P, Cu3P).

Main Results:

• Successfully synthesized phase-controlled cobalt phosphides (Co2P to CoP) using the hydrogel template.
• Demonstrated superior lithium storage performance with cobalt phosphides, achieving 495.2 mAh g-1 after 1000 cycles at 2.0 A g-1.
• Validated the hydrogel route's versatility by synthesizing other TMPs.

Conclusions:

• The semi-IPN hydrogel approach offers a safe, scalable, and effective route for phase-controlled TMP synthesis.
• This method provides a new strategy for designing advanced inorganic materials from functional hydrogels for sustainable energy development.
• The synthesized cobalt phosphides exhibit excellent electrochemical performance, highlighting their potential in energy storage devices.