Converting waste paper into stronger and more durable electrodes

Converting paper waste into stronger and more durable electrodes

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a technology to convertwaste paper, from single-use packages and bags, cardboard boxes, paper Kraft turned into a basic component of lithium-ion batteries, through a process called “carbonization,” which turns paper into pure carbon, so that researchers can transform paper fibers into electrodes that can be converted into rechargeable batteries that power cell phones, medical equipment, and vehicles. Electrical.

To achieve this, the team exposed the paper to high temperature; Which led to its dissolution into pure carbon, water vapor, and some oils that can be used as biofuel. Because carbonization occurs in the absence of oxygen, it emits small amounts of carbon dioxide, and the process is a greener alternative to disposing of paper by incineration, which produces large amounts of Greenhouse Gases (GHGs).

A sustainable alternative to current manufacturing methods

The carbon electrodes produced by the research team also demonstrated superior durability, flexibility, and significant “electrochemical” properties, as laboratory tests showed that these electrodes can be charged and discharged up to “1200” times, which is no less than Poor durability of the electrodes in the batteries currently used in phones. Batteries that use electrodes made from carbon produced from kraft paper can withstand greater physical stress than their counterparts, as they absorb impact energy up to five times better.

The method developed by NTU also uses less energy and heavy metal-intensive processes than current industrial methods for manufacturing battery electrodes, and since the value of the electrode ranges from 10 percent to 15 percent of the total cost of a lithium-ion battery, it is also expected that This innovative method significantly reduces the cost of manufacturing electrodes.

Using waste paperKraft as raw materials for the production of battery electrodes would also reduce our dependence on traditional sources of carbon, such as: “carbon fillers” and carbon-producing binders, which are subsequently mined and processed. With chemicals and heavy machinery.

Converting waste into products

Paper waste, which consists of cardboard bags, newspapers and other paper packaging, accounted for nearly a fifth of the waste generated in Singapore in 2020, and among these wastes we find that kraft paper bags can have significant environmental impacts compared to alternatives. Others made of cotton and plastic, due to the largest contribution of this type of paper to global warming when burned.

The current innovation, which offers an opportunity to recycle paper waste, reduce our dependence on fossil fuels, and accelerate our transition towards a circular economy, green materials, and clean energy, reflects Nanyang University’s commitment to reducing our impact on the environment, and is one of four major humanitarian challenges that the university seeks to address through Its strategic plan 2025 NTU.

Assistant Professor Lai Shangquan, from the School of Mechanical and Aerospace Engineering - Nanyang Technological University, who led the project, said: “Kraft paper is used in many aspects of our daily life, from gift wrapping, arts and crafts, to a countless number of uses. Industrial, such as: heavy-duty containers and protective packaging. However, little has been done to manage it intelligently when disposed of as waste, as it is mostly incinerated; Which generated high levels of carbon emissions.”

He added: “The new innovative method gives various paper waste a new chance in life, as the paper was directed to the production of batteries. This is to meet the growing need for devices such as electric cars and smart phones, which will not only help reduce carbon emissions, but will also reduce dependence on mining methods and heavy industry.” “Our discovery is unique in that we have succeeded in transforming a common and ubiquitous material - paper - into another extremely durable and highly sought-after material (electrodes), and we hope that this technology will serve the world’s rapidly growing need for a sustainable and greener material for batteries, which has been demonstrated Its improper manufacturing and management has a negative impact on our environment.”

Distinctive characteristics of the produced electrodes

To produce the carbon electrodes, Nanyang Technological University researchers cut several thin sheets of paper with a laser to form different lattice geometries. They then heated the paper to “1200 degrees Celsius” in an oven without the presence of oxygen, to convert it to carbon, and form the electrodes.

The research team attributes the superior strength, flexibility and electrochemical properties of the resulting electrodes to the arrangement of the paper fibres. It is also worth noting that the combination of strength and mechanical durability demonstrated by electrodes made from waste paper will allow batteries for phones, laptops and cars to better withstand shocks, which could prevent many accidents.

Current lithium battery technology relies on internal carbon electrodes that gradually crack and collapse after a number of drops and shocks, which is one of the main reasons why battery life becomes shorter over time. The researchers say their electrodes, which are stronger than current electrodes used in batteries, will help address this problem and extend the life of batteries in a wide range of uses, from electronics to electric cars.

In the same context, engineer Lim Gao Yao, an engineer participating in the research from the College of Mechanical and Aerospace Engineering at Nanyang University, said: “The electrodes that we produced showed a set of strengths, such as: durability, shock absorption, and electrical conductivity, and these properties demonstrate Structural and functional: Electrodes made of kraft paper are a sustainable and scalable alternative compared to the electrodes currently used.”

Finally, the research team will conduct further research; To reduce the thermal energy needed to convert paper into carbon, and then into electrodes.