Smart Microfluidics Towards Low-Cost High-Performance Li-Ion Batteries

The cost of Li-ion batteries (LIBs) is presently the largest barrier to the electrification of road transport. Battery pack cost needs to be halved to $125/kWh (USABC target) in order to get electric vehicles (EVs) ready for mass market penetration by 2040, thereby helping the UK to meet its legislated emission reduction target of 80% for 2050. Meanwhile, the energy and power density of LIBs also need to be significantly increased to reduce the consumers' range anxiety. Transport in the electrolyte plays a key role in determining the cost, performance and lifetime of a LIB cell, and can be linked to all the above key barriers to mass EV adoption. Particularly, transport in the electrolyte has been found to become the major limiting mechanism to the high-power operation of LIBs, as well as to the pursuit of thick electrodes which is being widely considered as a near-term solution to energy density increase and cost reduction for EV batteries. However, the present LIB designs with static electrolytes provide little room for improving and engineering the electrolyte-side transport processes. Therefore, radical innovations in the engineering design of LIB cells are urgently needed to address the electrolyte-side limitations to meet ever fast increasing performance of electrode active materials. Relying on the unique features of microfluidics including easy integration, rapid heat and mass transfer and precision control, this Fellowship aims to develop a novel microfluidic-based approach to engineering the transport processes in the electrolyte of LIBs, with the goal of improving cell energy and power density and reducing cost. To achieve this aim, the Fellowship will first combine integrated microfluidics and fluorescence microscopy to develop an easily accessible, multiscale, multichannel tool for characterising the coupled thermal-hydro-electrochemical dynamics and its interplay with electrode microstructures in a LIB cell during operation, underpinning further technological innovations. The Fellowship will then conduct a systematic model-based parametric study to develop directional microfluidic designs for LIB cells and to develop microfluidic principles for manipulating the fluid flow, local composition, temperature and electrochemical processes in the new cell design for optimal performance. The Fellowship will finally explore high-efficiency upscaling strategies for the new cell design and analyse their economic feasibilities for EV applications.