![]() ![]() As a result, Li-S batteries suffer from rapid capacity fade, significant self-discharge issues and the practical capacity and cycle life achieved have been lower than expected. Other problems include the deposition of non-soluble Li 2S on the surfaces of both the cathode and the anode as well as disproportionation reactions occurring in the electrolyte. 80% increase in volume) due to the reduction of elemental sulfur to Li 2S (density of S is 2.03 g cm −3, whilst density of Li 2S is 1.66 g cm −3) 6, 7, 8, 9. ![]() These limitations stem from the electrically insulating nature of sulfur dissolution of highly soluble lithium polysulfide intermediates that occur during cell charge and discharge and large volume changes during the conversion reaction (ca. Furthermore, elemental sulfur in Li-S batteries has the advantage of being abundant, low cost and relatively non-toxic compared to the transition metal oxides used in conventional Li-ion batteries 6, 7.ĭespite intensive research, Li-S batteries have not yet achieved widespread commercialisation due to challenges stemming from the highly complex phenomena occurring in Li-S cell chemistry that have yet to be fully understood and overcome. The lithium sulfur (Li-S) battery is one such system, having a theoretical specific energy density and specific capacity of 2567 Wh kg − mAh g −1, respectively which is significantly higher than that of conventional Li-ion batteries 5. Therefore, there is increasing research interest in conversion-type electrodes that promise higher energy densities. However, certain limitations exist in current intercalation-type cathode based lithium-ion battery (Li-ion) technologies – primarily related to their cost, safety and the limit of energy density 1, 2, 3, 4. Lithium-based batteries are one of the most promising electrochemical energy storage technologies available, due to the high energy density and prolonged cycle life compared with other rechargeable battery systems (Pb, Ni-Cd, Ni-MH). We anticipate that X-ray tomography will be a powerful tool for optimization of electrode structures for Li-S batteries. Finally, we demonstrate the nano-scopic length-scale required for the features of the carbon binder domain to become discernible, confirming the need for future work on in-situ nano-tomography. Furthermore, we report a shift towards larger particle sizes and a decrease in volume specific surface area with cycling, suggesting sulfur agglomeration. Here we show the uneven distribution of the sulfur phase fraction within the electrode thickness as a function of charge cycles, suggesting significant mass transport limitations within thick-film sulfur cathodes. For the first time to the authors’ knowledge, a multi-scale 3D in-situ tomography approach is used to characterize morphological parameters and track microstructural evolution of the sulfur cathode across multiple charge cycles. However, the multiple reactions and phase changes in the sulfur conversion cathode result in highly complex phenomena that significantly impact cycling life. Lithium sulfur (Li-S) batteries offer higher theoretical specific capacity, lower cost and enhanced safety compared to current Li-ion battery technology. ![]()
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