Nanocomposite Energy Storage Materials Based on Intercalation Transition Metal Oxides and Poly(3,4-ethylenedioxythiophene)

Grant Number: 16-03-00457

Project Description

This project aims to synthesize and study new energy storage materials for electrochemical lithium-ion supercapacitors. The central strategy for obtaining materials with improved characteristics (higher energy and power, extended cycling lifetime) involves leveraging materials used in lithium-ion batteries and enhancing their properties via two key modifications:

1. Surface thin-layer modification of active material grains (e.g., LiMn₂O₄, LiMn₂O₄ coated with SnO₂ shell, Li₄Ti₅O₁₂) with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT):

   • Increases conductivity of the material
   • Stabilizes the inorganic component, reducing its degradation
   • Facilitates lithium ion intercalation/deintercalation in surface layers of inorganic grains

2. Use of new electrolyte compositions based on propylene carbonate and various ionic liquids:

   • Expands the electrochemical operating window
   • Extends working temperature range, particularly toward lower temperatures
   • Improves operational safety of supercapacitors

The project plans to produce two main types of nanostructured materials:

• Core-shell structures, where active material grains are coated with PEDOT shell
• Bulk-distributed structures, created from colloidal dispersions of inorganic active material with PEDOT:PSS (poly(3,4-ethylenedioxythiophene/polystyrene sulfonate)) and added carbon materials

Research focus:

• Study the effect of polymer additives, especially shell thickness in encapsulated grain, as well as structural-morphological factors and electrolyte nature on rechargeable material electrochemistry
• Employ high-dispersity intercalation oxides in conductive matrices and surface modification to pursue enhanced cycling stability, higher power output, and increased charge/discharge currents

Planned characterization:

• Structure using TEM/SEM, energy-dispersive analysis, and other structural-physical methods
• Energy storage properties via cyclic voltammetry, electrochemical impedance, and charge/discharge profiles

Key objective: Systematic investigation of the impact of component structural and size factors on the electrochemical performance of composite materials, laying groundwork for advances in physical-chemical principles of nanocomposite stabilization, charge transfer in hybrid rechargeable materials, and targeted property optimization.