What will batteries of the future be made of? Four scientists discuss the options

In this Conversation Weekly episode, researchers investigate sustainable battery technologies that power environmental sensing in challenging environments. Terracel, a soil-powered fuel cell, offers a way to run wireless sensors in soggy bio-swirl ecosystems without relying on traditional batteries. The program also surveys lithium-ion alternatives, including sodium-ion and solid-state chemistries, and a novel waste-derived battery that can be repurposed into fertiliser at the end of life. Discussions cover the science of how these batteries work, geopolitical and resource concerns around critical minerals, and strategies to scale energy storage for a more connected, greener world. The episode features researchers from Chicago, the UK, and Dubai, highlighting the broad effort to reinvent batteries for environmental resilience and sustainable data collection.

Overview

The Conversation Weekly episode centers on the search for sustainable, scalable batteries to power environmental sensing in difficult environments, from swampy Chicago bio-swirl infrastructures to dry soils. At the heart of the discussion is Terracel, a soil-powered microbe fuel cell designed to harvest energy from ubiquitous organic carbon in the soil. The goal is to enable reliable wireless sensors in places where conventional batteries fail or are hard to retrieve after burial, such as wetlands and green infrastructure. The program also surveys a wider landscape of battery research, including lithium-ion alternatives like sodium-ion and solid-state chemistries, as well as fully biodegradable or recyclable options based on waste streams. These lines of work reflect a broader push to decarbonize energy storage while reducing e-waste as sensor networks scale up globally.

Terracel and In-Situ Power for Green Infrastructure

Bill Yen, a PhD candidate in electrical engineering at Stanford, describes Terracel as a fuel cell that generates power using microbes in the soil. Unlike conventional batteries, Terracel draws energy from the soil’s organic carbon, enabling sensors to be buried in conditions where metals or solar panels would fail due to mud or flooding. The device is compact, about the size of a paperback, with the anode and cathode arranged to facilitate microbial digestion and electrochemical reaction. Yen notes that the soil itself becomes the energy source and the device can operate in wet, dirty environments where electronics typically vanish. The broader aim is to power environmental sensors in real-world settings while avoiding the environmental and logistical downsides of traditional batteries.

"If you try to put a battery there, it is impossible to retrieve, right, because you're burying it in essentially pretty much a swamp. So we were thinking, OK, what is the one resource that is present in all these environments that we can take advantage of to generate power and that is the soil." - Bill Yen, PhD candidate in electrical engineering at Stanford

Battery Chemistry: Diversification Beyond Lithium

The episode then expands to the broader field of battery research. Laurence Hardwick, a professor of electrochemistry at the University of Liverpool, explains how batteries function at a fundamental level: two electrodes separated by an electrolyte, with ions moving to balance charge and deliver energy. The discussion highlights why lithium-ion cells dominate today—high energy density and non-aqueous electrolytes enable voltages around 4 volts—but also why researchers are exploring alternatives as the scale of energy storage grows. The concerns cited include resource constraints, geopolitical dependencies, and the volatility of mineral prices, particularly lithium. A consortium in the UK is examining sodium-ion batteries as a potential pathway, noting that abundant sodium and iron-based chemistries could reduce supply risks and price volatility associated with cobalt and nickel.

"Diversification to alternative battery chemistries is obviously a good thing." - Robert Armstrong, chemist and researcher at the University of Saint Andrews

Biomaterials, Waste Streams and Biodegradable Batteries

Ulugbek (Ulubek) Azimov of Northumbria University discusses bioower cells, a battery concept derived from waste streams such as coffee and agricultural byproducts. Their approach aims to avoid lithium, cobalt, and nickel entirely, using plant-based materials and a gel electrolyte. The battery is designed to be fully recyclable or repurposed as liquid fertiliser, aligning with circular economy principles. While current energy density trails conventional lithium-ion systems, the researchers see residential energy storage as a viable initial market and plan to scale to industrial storage. This line of work emphasizes end-of-life sustainability and the potential to turn waste into a useful energy resource while remaining aligned with agricultural and environmental needs.

"We are trying to develop a biodegradable battery which does not use any lithium, cobalt, nickel, or any other earth metals, and it will be fully recyclable or repurposed at the end of its life span into liquid ionic fertiliser." - Ulugbek Azimov, associate professor at Northumbria University

Solid-State Batteries and the Road Ahead

The conversation also covers solid-state batteries and their potential safety and energy-density advantages. Lawrence Hardwick explains that solid-state systems replace flammable liquid electrolytes with ceramic materials and fixed hopping sites for ions, which can improve safety and possibly enable higher energy densities. Despite progress, ion conduction in solid electrolytes remains a challenge, and real-world scaling is a work in progress. Car manufacturers such as Toyota have already invested heavily in solid-state research as part of the broader pursuit of more robust energy storage solutions for electric vehicles and grid storage. The EU’s upcoming battery passport regulation, effective February 2027, is presented as a driver for standardisation and traceability across the battery lifecycle, incentivising investment in safer, lower-risk materials and manufacturing processes.

"They offer a lot of potential energy gaining benefits and safety benefits." - Laurence Hardwick

Future Directions: A Multi-Path Battery Landscape

Looking to the future, the podcast suggests a diversified ecosystem of battery technologies rather than a single universal solution. Smaller electric vehicles may operate well on sodium-ion chemistries, while large-scale energy storage could benefit from low-transition-metal or nickel-free materials. The possibility of revisiting earlier concepts such as aqueous systems with high salt concentrations is discussed as researchers seek safer, cheaper, and more abundant alternatives. The overarching message is that, as the demand for energy storage explodes with sensor networks and electrified infrastructure, a portfolio of battery technologies will likely coexist, guided by resource availability, environmental impact, and policy developments.

Conclusion: Toward a Sustainable, Scalable Battery Future

The episode closes with reflections on the practical steps needed to bring these technologies to market while minimising environmental harm. It notes ongoing collaborations across universities and industry, including funding and recognition from innovation programs like Prototypes for Humanity, to accelerate the testing and deployment of sustainable battery solutions. The overarching theme is that powering an increasingly data-rich world will require batteries designed for end-of-life stewardship, supported by responsible materials choices and robust infrastructure for recycling and repurposing.

"People talk about scaling up the Internet of Things, deploying more sensors, more technology, but what happens to all these technologies at end of life, they become e-waste." - Bill Yen, PhD candidate in electrical engineering at Stanford