Scientists turn waste paper into battery parts for smartphones and electric cars

Scientists from Nanyang Technological University (NTU Singapore) in Singapore have developed a technology that can turn waste paper from single-use packaging, bags and cardboard boxes into key components
of lithium-ion batteries.

Through the carbonization process of converting paper into pure carbon, NTU researchers converted the fibers of the paper into electrodes that can be made into rechargeable batteries to power
mobile phones, medical devices, and electric vehicles.

To carbonize the paper, the team exposed the paper to high temperatures, reducing it to pure carbon, water vapor, and oil
that could be used for biofuels.
Since carbonization is carried out without oxygen, it emits negligible carbon dioxide, and the process is more environmentally friendly than burning kraft paper, which produces a lot of greenhouse gases
.

The carbon anodes produced by the research team also exhibit superior durability, flexibility and electrochemical performance
.
Laboratory tests have shown that this anode can be charged and discharged 1200 times, at least twice as many as the current mobile phone battery anode
.
Batteries made with anodes made from NTU can also withstand more physical stress than other batteries, absorbing crushing energy five times
more than other batteries.

The method developed by NTU uses fewer energy-intensive processes and heavy metals
than current industrial methods for manufacturing battery anodes.
Since the value of the anode accounts for 10% to 15% of the total cost of lithium-ion batteries [1], this latest method of using low-cost scrap is also expected to reduce production costs
.

The findings were published in the October issue of the peer-reviewed scientific journal Additive Manufacturing
.

Using waste paper as a feedstock for battery anodes will also reduce our reliance on traditional carbon sources such as carbonaceous fillers and carbon-producing binders, which are mined and then processed
with harsh chemicals and machinery.

Paper waste, including discarded paper bags, cardboard, newspapers and other paper packaging, accounted for nearly one-fifth of the waste generated in Singapore in 2020[2].

An independent study by NTU in 2020[3] found that kraft paper bags make up the majority of waste paper in Singapore compared to paper bags made from cotton and plastic, and kraft paper bags have also been found to have a large environmental footprint
due to their greater contribution to global warming when incinerated and greater ecotoxic potential for their production.

Current innovations provide an opportunity to upcycle used products, reduce our dependence on fossil fuels and accelerate our transition to a circular economy, green materials and clean energy, reflecting NTU's commitment to mitigating our environmental impact, one of
the four challenges that NTU seeks to address through its 2025 Strategic Plan.

Lai Changquan, assistant professor in Nanyang Technological University's School of Mechanical and Aerospace Engineering, who led the project, said: "Paper has applications in many aspects of our daily lives, from gift wrapping and crafts, to countless industrial uses such as heavy-duty packaging, protective packaging and building fill-in-the-blanks
.
" However, apart from incineration, people do little to manage their waste when disposing of it, as the composition of the waste generates a lot of carbon emissions
.
Our approach is to revitalize kraft paper and use it to meet the growing demand for devices such as electric vehicles and smartphones, which will not only help reduce carbon emissions, but also reduce
reliance on mining and heavy industry methods.
”

The research team has applied for a patent
with NTUTIVE, an innovative and entrepreneurial company at Nanyang Technological University.
They are also working to commercialize
their inventions.

Recipe for green battery parts

To produce the carbon anode , researchers at Nanyang Technological University joined several sheets of kraft paper and laser cut them to form different geometric lattices , somewhat similar to spires , similar to spires pi?ata
.
The paper is then heated to 1200°C in a furnace without oxygen, converting it to carbon, forming an anode
.

The research team at Nanyang Technological University attributed the superior durability, flexibility and electrochemical performance of this anode to the arrangement
of the paper fibers.
They say the strength and mechanical toughness shown by the anodes made by NTU will make cell phones, laptops and car batteries better withstand the impact
of falls and collisions.

Current lithium-ion battery technology relies on internal carbon electrodes, which gradually break and shatter under the physical impact of a drop, which is one of the
main reasons why battery life becomes shorter over time.

The researchers say their anode is more durable than the electrodes currently used in batteries and will help solve this problem and extend the life
of the battery in a wide range of uses, from electronics to electric vehicles.

Mr Lim Guo Yao, a research engineer at Nanyang Technological University's School of Mechanical and Aerospace Engineering, said co-author of the study, "Our anode shows a combination of strengths such as durability, shock absorption, electrical conductivity, which are not available in current materials
.
These structural and functional properties show that our kraft paper-based anodes are a sustainable and scalable alternative to current carbon materials and will find economic value in demanding high-end, multifunctional applications, such as the emerging field
of structural batteries.
”

Assistant Professor Lai added: "Our approach transforms a common and ubiquitous material – paper – into another material
that is very durable and in high demand.
We hope that our anodes will serve the world's rapidly growing demand for sustainable and more environmentally friendly battery materials, the manufacture of batteries and improper waste management that have proven to have a negative impact
on our environment.
”

Juan Hinestroza, a professor in the Department of Design at Cornell University's Human Center who was not involved in the study, emphasized the importance of the work done by the NTU research team, saying: "Since the production of kraft paper is very large and similar treatments are available all over the world, I believe that the creative approach pioneered by NTU researchers in Singapore has great potential
for impact on a global scale.
" Any discovery that can use waste as a raw material for the production of high-value products such as electrodes and foams is a huge contribution
.
I think this work may open up a new avenue and inspire other researchers to look for conversion pathways for other cellulose-based matrices, such as textiles and packaging materials, which are massively discarded
globally.
”

The research team at Nanyang Technological University will conduct further research to improve the energy storage capacity of their materials and minimize the thermal energy
required to convert paper into carbon.

Concentrate:

Lux Research, Inc
.
Lithium-ion battery innovation roadmap (2019).

[2] National Environmental Protection Authority
of Singapore.
Reduce total waste generation and waste sent to Semacau landfill in 2020 (2021).

Nanyang Technological University
.
Scientists at NTU in Singapore report that plastic bags may be more "environmentally friendly" than paper and cotton bags in cities such as Singapore (2020).

Journal Reference:

1. Chang Quan Lai, Guo Yao Lim, Kai Jie Tai, Kang Jueh Dominic Lim, Linghui Yu, Pawan K.
   Kanaujia, Peiyuan Ian Seetoh.
   Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper.
   Additive Manufacturing, 2022; 58: 102992 DOI: 10.
   1016/j.
   addma.
   2022.
   102992