Scientists from Nanyang Technological University, Singapore (NTU Singapore; www.ntu.edu.sg) have developed a technique to convert waste paper, from single-use packaging, bags and cardboard boxes, into electrodes, which can be made into rechargeable batteries that power mobile phones, medical equipment and electric vehicles. To carbonize the paper, the team exposed the paper to high temperatures, which reduced it to pure carbon, water vapor and oils that can be used for biofuel. Because the carbonization takes place in the absence of oxygen, the process emits negligible amounts of carbon dioxide, so the process is a “greener” alternative to disposing of waste kraft paper by incineration.
To produce the carbon anodes, the NTU researchers joined and laser cut several thin sheets of kraft paper to form different lattice geometries. The paper was then heated to 1,200°C in a furnace without the presence of O2, to convert it into carbon, forming the anodes. Anodes produced by the research team also demonstrated superior durability, flexibility and electrochemical properties. As reported in a recent issue of Additive Manufacturing, laboratory tests showed that the anodes could be charged and discharged up to 1,200 times, which is at least twice as durable as anodes in current phone batteries. Batteries with these anodes could also withstand more physical stress than their counterparts, absorbing crushing energy up to five times better. The researchers attribute the anode’s superior durability, flexibility and electrochemical properties to the arrangement of the paper fibers.
The research team has filed for a patent with NTUitive, NTU’s innovation and enterprise company. They are also working towards commercializing their technology.