New technique offers sustainable solution for disposal of fiber-reinforced plastics

The flash upcycling method addresses the urgent need for recycling fiber-reinforced plastic, diverting it from landfills and incinerators, thus reducing waste and environmental harm. A recent study by Dr. James Tour and colleagues from Rice University, published by Cambridge University Press, reveals that silicon carbide (SiC) powders derived from this process enhance the performance of lithium-ion batteries, contributing to sustainability efforts.

The escalating use of fiber-reinforced plastic underscores the necessity for effective recycling methods as these materials reach their lifespan's end. Presently, prevalent disposal practices raise concerns due to their contribution to resource depletion and environmental damage. Silicon and plastic materials, primarily sourced from fiber-reinforced plastic waste, typically end up in landfills or are incinerated - a process that contributes to resource wastage and environmental degradation.

In response to these challenges, researchers have developed an innovative solvent-free and energy-efficient flash upcycling technique. Retired wind turbines and aircraft, which are often disposed of in large landfill pits, can be repurposed through this new process into valuable silicon carbide powders. This closed-loop scenario exemplifies sustainability by transforming fiber-reinforced plastic waste into useful materials while reducing environmental pollution and resource waste. The novel method swiftly converts mixtures of glass fiber-reinforced plastic and carbon fiber-reinforced plastic into SiC powders within seconds, achieving yields exceeding 90%. By adjusting input pulse voltages and flash durations, the technique allows for the selective synthesis of two distinct SiC phases - 3C-SiC and 6H-SiC - each with phase purities ranging from 90% to 99%.

Further investigation into the phase transformation process highlights the significant role played by increasing silicon vacancy content during the flash process. This is particularly notable in the transition from 3C-SiC to 6H-SiC. Additionally, the derived SiC powders demonstrate versatility as anode materials for lithium-ion batteries, displaying phase-dependent performance characteristics.

The superior reversible capacity and rate performance of the 3C-SiC anode compared to its 6H-SiC counterpart is significant. Both maintain exceptional cycling stability, retaining approximately 95% of their capacity after 200 cycles. Comprehensive life cycle assessments underscore the environmental benefits of the flash upcycling method, indicating substantial reductions in energy consumption, greenhouse gas emissions, and water usage when compared to alternative recycling approaches.

Cambridge Open Engage: Yi Cheng, et al., Flash upcycling of waste glass fiber-reinforced plastics to phase-controllable silicon carbide, ChemRxiv (2023). DOI: 10.26434/chemrxiv-2023-bb9b0