Energy

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Within the energy theme, we have two research areas:
1. Energy storage
2. Carbon capture

Energy storage
The UK government is prioritising energy storage technologies in order to become a global leader (“Building our Industrial Strategy: green paper”). Lithium-ion batteries (LIBs) are a vital technology in this area. However, their manufacture is prodigiously wasteful, which creates an enormous burden on the environment and is unsustainable. Hence more sustainable synthesis routes are urgently needed.

We are focusing on:

Discovery of green synthesis methods for energy storage materials (Si, silica and Co-oxides).
Developing scalable and sustainable processes for their manufacturing.
Performing techno-economic-sustainability analyses.

We have recently started various projects on Green routes to energy storage materials.

Specifically, we are working on following areas:

We have identified Magnesiothermic Reduction (MgTR) of silica to silicon as process suitable for large scale manufacturing of mesoporous silicon. We are building a detailed understanding of the evolution of pore properties during the MgTR reaction and its effects on the performance of porous silica produced. This will enable a predictive design of a method to produce mesoporous silicon structures for lithium-ion battery anodes. Recently, we showed that the interconnectivity of silicon crystallites determines the final mesoporosity. Applying this mechanism to bioinspired silica enabled us to produce mesoporous silicon with a capacity of 2170 mA h/g after 100 cycles.
A second challenge is the scalability of MgTR is affected by the large excess heat produced during reaction. Thermal moderator can be used to mitigate this issue, but their use is not fully understood. We have carefully investigated the role of a thermal moderator and identified the critical factors for controlling scale-up and the product properties. Our results have established pathways for scaling-up this method such that it can now be taken forward to target specific porous silicon properties.
The direct use of silica as a lithium-ion battery anode material typically requires a pre-treatment step to induce electrochemical activity. Up to now, the electrochemical reduction pathway and the nature of the products this give rise to are unknown. We uncovered the electrochemical reduction pathway and, for the first time, identify elemental silicon as a reduction product. These insights contribute towards our understanding of the electrochemical reduction of silica and can enable economically viable, silica-based electrodes for next generation lithium-ion batteries.

Relevant Publications

J. Entwistle, A. Rennie and S. V. Patwardhan, A Review of magnesiothermic reduction of silica to porous silicon for lithium-ion battery applications and beyond. Journal of Materials Chemistry A, 6, 18344-18356, 2018. Featured on the journal's cover.
Jake E. Entwistle, Gregory Beaucage and Siddharth V. Patwardhan, Mechanistic understanding of pore evolution enables high performance mesoporous silicon production for lithium-ion batteries. J. Mater. Chem. A, 2020, 8, 4938 - 4949.
Jake E. Entwistle and Siddharth V. Patwardhan, Enabling scale-up of mesoporous silicon for lithium-ion batteries: a systematic study of a thermal moderator, RSC Adv., 2021, 11, 3801-3807.
Jake E. Entwistle, Samuel G. Booth, Dean S. Keeble, Faisal Ayub, Maximilian Yan, Serena A. Corr, Denis J. Cumming and Siddharth V. Patwardhan, Insights into the Electrochemical Reduction Products and Processes in Silica Anodes for Next‐Generation Lithium‐Ion Batteries. Adv. Energy Mater., 2020, 10, 2001826.

Collaborators: Energy storage and its applications (EPSRC CDT).
Funding: EPSRC

Carbon capture
The increasing desire for climate change mitigation, driven by the need to comply with international legislation, has seen an increase in carbon capture methods, many of which are designed as post-combustion methods suitable for the energy generation sector.

Existing carbon capture methods have many disadvantages, such as prohibitive cost of scale-up and excessive toxic, corrosive waste and high regenerative costs.

We are focusing on:

Synthesis of novel green nanomaterials for carbon capture.
Analysis for CO2 adsorption capacity and kinetics of adsorption.
Correlating synthesis-property-carbon capture performance.
Building bench-top capabilities for testing novel adsorbents in continuous operation.

Relevant Publications/Conference presentations

T. Yip, et al., Novel Approaches to the Preparation and Exploitation of Carbon Capture Materials, poster presented at the UKCCSRC's conference on CCS in the Bigger Picture Agenda, 2014.
S. Patwardhan, Invited talk on "CO2 Capture using Green Nanomaterials" in SCCS organised Tackling Industry’s Carbon Emissions 2nd workshop which brought together industry, government and academia, 2013.
Forsyth, C., Yip, T. W. S. & Patwardhan, S. V. CO2 sequestration by enzyme immobilized onto bioinspired silica. Chem. Commun. 49, 3191-3193 (2013). [Link]

Inside Cover Chem. Commun., 2013, 49, 3162-3162 [Link]

Collaborators: Dr. A. J. Fletcher (Strathclyde), Dr. M. Sweatman (Edinburgh).
Funding: EPSRC, Bridging the Gap