Self-healing lithium-ion batteries enabled by fiber/nano optic sensing and convergent data-driven analytics

The importance and impact of lithium-ion batteries in the early 21st century has been profound. However, despite the concurrent interest in sustainable living, the fact that lithium-ion batteries cannot be repaired or serviced during their lifetime results in a growing dilemma: should we, as a society, be investing so heavily in this technology if the devices have a determinate and finite lifetime? One way to mitigate such a conundrum is to explore ‘self-healing’ batteries; in the same way that the human body has an immune system to assist with its state-of-health, can lithium-ion batteries also be made more robust, such that a small external stimuli or ‘medicine’ might be able remove deleterious molecules or quench unwanted parasitic reactions inside the battery. However, in order to eliminate the alchemy behind guessing at the cause of why and how the battery is degrading, new monitoring and sensing approaches must be utilized. With this in mind, the use of fiber optic sensors is highly appealing in the area of lithium-ion batteries because of their general compatibility including many factors: chemical, electrical, geometric, etc. In this project, we aim to bridge the gap between repairable batteries and fiber optic sensing. With the use of robust electrochemical methods, novel in-house X-ray computational tomography techniques, and the most promising chemo-mechanical materials from other researchers around the world, we will be able to understand how and why some lithium-ion batteries degrade, and then target specific courses of action to mitigate and improve their overall state-of-health.

Lithium-ion batteries have become a ubiquitous part of modern society, enabling a new era of electric vehicles and energy storage systems, in addition to an ever-increasing range of consumer electronics products. In contrast to solid state electronics, batteries have a finite lifetime and cannot last forever. Even more concerning is that with their high energy density, accidents and safety incidents can present serious hazards. Being able to quantitatively monitor the state of health of batteries nondestructively and during usage is essential to both further improvement and better understanding of their limitations and performance. X-ray computed tomography is well-suited for in-situ/operando studies of battery related processes and assemblies, however, it is expensive, and unsuitable for battery health monitoring on a commercial scale. Optical fibers, notably fiber Bragg gratings, constitute a complementary low-cost and light-weight technology, enabling temperature, chemical environment, and mechanical strain to be measured in small form factor batteries. With their inert chemical nature, they can even be placed inside battery cells during operation, despite the harsh electrochemical environment. For the HeaLiSelf project, our working hypothesis is that data collected from fiber Bragg grating sensors will serve as a highly efficient proxy for X-ray computed tomography observations. Novel binder and additive chemistries are promising approaches to introduce self-healing into batteries, but tan effective system combining physical observations and effective sensors will bring self-healing batteries one step closer towards the real-world, and this is the vision for the HeaLiSelf project. The strategy of HealLiSelf relies on the convergence of fiber optic sensing, nanoscale material characterization, and advanced data analytics.