Facile Preparation of High Performance Low Concentration HCHO Degradation Catalyst from Waste Li-MnO2 Batteries

Abstract

The recycling and utilization of lithium-ion batteries has received a lot of attention. The use of recycled waste lithium-manganese batteries to degrade formaldehyde contaminated gas by adsorption is certainly killing two birds with one stone. In this paper, efficient catalysts capable of degrading formaldehyde were obtained using lithium-manganese button batteries being discharged to different levels and then recovering the cathode material by a simple method and labelled as LixMnO2 (x = 0.00; 0.25; 0.50; 0.75; 1.00). The fully discharged cathode material Li1.00-MnO2 degraded formaldehyde at nearly 100% (less than 0.1 ppm) within 24 h at room temperature, which is twice the degradation rate of the undischarged cathode material. The high degradation efficiency is attributed to the continuous doping of Li+ as the discharge proceeds and the conversion of Mn(IV) to Mn(III), so the lattice gap, defects, surface oxygen species and specific surface area of the catalyst increase. And the surface oxygen involved in the degradation of formaldehyde increases. The catalytic activity of the catalyst for formaldehyde gradually increased with the discharge, promoting the catalytic degradation effect. The degradation rate of formaldehyde at low concentrations was close to 100% within 24 h. This study provides an attractive approach for converting lithium battery electrode materials into formaldehyde degradation catalysts to improve the indoor environment.