Quasi-closed-loop approach for facile and environmentally friendly red mud reutilization as advanced Li-ion anode material

A huge amount of red mud was produced in the Aluminum industry which is environmentally hazardous and hard to de-alkalize or recycle due to its enormous amount and low value for recycling. To solve the problem of red mud treatment, a facile, scalable, and environmentally friendly quasi-closed-loop approach for red mud recycling was utilized to recycle it as Li-ion battery anode material by a simply alkali-roasted carbon-coating method, which can effectively solve the problem of red mud treatment and recycle it as high-value Li-ion anode material. Alkali-roasted carbon-coating red mud (RA/C) shows remarkable electrochemical performance compared to current works related to red mud recycling and ferrosilicon-based anode materials, the initial reversible charge capacity reaches 1746 mA h g−1 at 0–3 V under 0.1 A g−1. Cycle-driven and pseudocapacitance-boosted enable RA/C to exhibit outstanding rate performance (1106 mA h g−1 at 10 A g−1 after 259 cycles compared to 910 mA h g−1 for initial discharge) and cycling performance (2538 mA h g−1 at 1 A g−1 after 500 cycles compared to 830 mA h g−1 for initial discharge). This work discussed dual mechanisms of cycle-driven and pseudocapacitance-boosted by dQm/dV plots, GITT (Galvanostatic Intermittent Titration Technique), and pseudocapacitance contribution measurement, revealing that higher cutoff potential induces electrochemical performance changes. The results show that the activation of the silicon oxide phase in 0–3 V promotes capacity increases in long-term cycling and capacitive contribution increases in 0–3 V significantly enhance the high current density discharge ability. Those attributes of red mud-based anode material become a promising candidate for low-cost and high-energy-density Li-ion batteries. This work provides estimations of economic feasibility and environmental impact, results show that quasi-closed-loop has high economic feasibility and low CO2-Eq. emission of 1.525 kg CO2-Eq. per kg RA/C compared to 9.616 kg CO2-Eq. per kg natural graphite of conventional natural graphite. This work proposed a feasible, sustainable, and scalable red mud recycling approach that promotes green and sustainable development of the Aluminum industry.