Upcycling Plastic Wastes into Graphites, Graphenes and Graphitic Carbons, for Electrochemical Energy Storage Devices

Smart overview of the Invention

The invention focuses on converting polymer waste, specifically polyethylene (PE) and polypropylene (PP), into graphite and graphitic porous carbons. This transformation is achieved through a novel process involving solid additives and air processing. The method addresses the challenges of oxygen diffusion in bulk polymer waste, significantly increasing char yield compared to processes without additives. The resulting materials exhibit excellent properties for use in electrochemical energy storage devices, such as lithium-ion battery anodes and supercapacitors.

Background

With the rising demand for lithium-ion batteries (LIBs), there is an urgent need for sustainable and abundant graphite sources. Traditional graphite production relies on non-renewable resources and energy-intensive processes, leading to environmental concerns. Plastic waste, which predominantly consists of carbon, presents a potential alternative feedstock for graphite production. However, converting plastics into highly crystalline graphite has been technically challenging due to issues like thermal decomposition during processing.

Technical Challenges

One of the primary obstacles in upcycling polyolefin-based plastics, such as PE and PP, is stabilizing the material for high-temperature processing. Standard methods lead to decomposition at relatively low temperatures, making it difficult to achieve the desired carbon forms. The innovation addresses this by using solid additives that facilitate oxygen diffusion into the polymer melt, enabling effective stabilization and subsequent conversion into high-quality graphite.

Innovative Approach

The method involves mixing solid additives with PE or PP melts during the pre-treatment phase. This technique enhances oxygen diffusion and increases the effective surface area of the melt, overcoming previous limitations in oxidative stabilization. The process allows for the stabilization of bulk forms of PE or PP wastes through a simple air processing method, enabling their conversion into highly crystalline bulk graphite powder suitable for LIB anodes.

Implications

This approach not only provides a sustainable method for managing plastic waste but also offers a viable alternative to traditional graphite production methods. By converting PE and PP waste into high-quality graphite powder, the invention supports the development of a more circular economy in electrochemical energy storage device manufacturing. This innovation has the potential to replace synthetic graphite currently used in commercial LIBs, contributing to both environmental sustainability and supply chain security.