Tech Insights

Can Paper Waste Make a Better Zinc-Based Battery?

June 06, 2024 by Jake Hertz

Standard lithium-ion batteries face numerous challenges, driving the need for more sustainable, affordable, and widely accessible solutions.

Batteries are crucial in the renewable energy landscape for storing excess energy generated from intermittent renewable sources. However, lithium-ion batteries, the current standard, face numerous challenges, including cost, material availability, and environmental concerns. These issues drive the need for more sustainable, affordable, and widely accessible solutions.

Linköping University researchers have developed an eco-friendly, long-life rechargeable aqueous zinc-lignin battery. The battery could offer a more affordable alternative to lithium-ion batteries. 

 

Zinc-lignin battery.

Zinc-lignin battery. Image used courtesy of Linköping University/Thor Balkhed

 

Exploring Lithium-Ion Challenges

Lithium-ion (Li-ion) batteries are currently used in various applications, including electric vehicles, owing to their high output voltage, energy-to-weight ratio, fast charging rates, and low self-discharge. However, Li-ions have notable drawbacks, including safety concerns, limited lithium and cobalt supplies, and a high carbon footprint. These challenges drive researchers to explore next-generation batteries using abundant, low-cost materials.

Battery performance is generally evaluated based on several key parameters, each critical for determining its suitability for various applications. 

  • The energy stored per unit volume or mass, or energy density, influences the battery’s size and weight. 
  • The battery’s cycle life indicates how many charge and discharge cycles happen before its capacity degrades, reflecting its longevity. 
  • Stability is crucial for maintaining performance over time, ensuring resistance to capacity loss and degradation under various conditions. 
  • Battery safety involves the design and materials to prevent overheating, fires, or explosions, ensuring secure operation. 
  • Environmental concerns address resource extraction, use and disposal, recycling, and carbon footprint.

 

Energy Solutions With Zinc, Lignin

Scientists at Linköping University have developed an eco-friendly and cost-effective battery solution to address energy challenges. This breakthrough technology utilized zinc and lignin.  Researchers claim it offers over 8,000 cycles while maintaining approximately 80% of its performance.

 

The zinc battery with lignin-carbon nanocomposite.

The zinc battery with lignin-carbon nanocomposite. Image used courtesy of Kumar et al.

 

Zinc-ion batteries (ZnBs) have attracted attention due to zinc's abundance, affordability, and low toxicity. Their redox potential, at -0.76 V versus the standard hydrogen electrode, enables operation in nonflammable aqueous electrolytes. Additionally, ZnBs offer a high theoretical specific capacity of 820 mAh g−1 and a large volumetric capacity of 5846 mAh mL−1. With over 99% recyclability of zinc metal from used batteries and low CO2 emission (45.1 kg) for 1 kWh charge storage capacity, ZnBs emerge as promising contenders in sustainable battery technologies, potentially rivaling LiBs in certain applications.

The battery’s primary components are lignin, a paper industry byproduct, and zinc, which is easily accessible, environmentally friendly, and cost-effective. The battery’s energy density matched that of lead-acid batteries but without the toxicity associated with lead. The battery maintained its charge for about one week, a notably longer duration than other zinc-based batteries, which typically discharge within a few hours. 

 

Lignin.

Lignin. Image used courtesy of Linköping University/Thor Balkhed

 

Generally, zinc batteries have suffered from poor durability mainly because zinc reacts with water in the electrolyte, generating hydrogen gas and causing dendritic growth, rendering the battery ineffective. To address this, researchers utilized a potassium polyacrylate-based water-in-polymer salt electrolyte to stabilize the zinc.

 

Powering the Future

By mitigating safety concerns and environmental impacts associated with Li-ions, this solution provides a scalable and recyclable energy storage alternative. The researchers envision scaling up production to create batteries as large as car batteries, leveraging zinc’s and lignin’s abundance and low cost. 

With support from various funding sources, the research team hopes to advance its eco-friendly technology and promote global access to sustainable energy solutions.