High Energy Lithium Sulfur Battery

In this project, Morrow Batteries AS and SINTEF jointly progress the research work towards preparation of high-performance/cost Lithium-Sulphur (LiS) batteries to support the transition to a carbon-neutral society. The battery will potentially have a practical gravimetric energy density roughly double that of the best Li-ion batteries. Other advantages comprise lower cost of materials, lower environmental impact of production (no use of cobalt or nickel), improved low-temperature performance and reduced risk of thermal run-away safety hazards. Morrow Batteries AS has developed a graphene stabilized sulphur cathode based on proprietary technology, that already matches the best state-of-the-art reported in the literature. Morrow Batteries AS has developed a graphene stabilized sulphur cathode based on proprietary technology, that already matches the best state-of-the-art reported in the literature. The main objective of the cathode study was to improve the mechanical strength without compromising energy density. Doing so required us to tailor the polymer coating process of the developed carbon sponge while maintaining reasonable electrode impedance. Various carbon/binder ratios were tested and the composition that yields the optimum mechanical strength/impedance was chosen for further studies. This improvement opens up the way for R2R manufacturing which is a prerequisite for commercial cell production. However, in order to produce a battery, an anode and electrolyte compatible with the cathode is needed. Lithium metal has the highest charge density among anodes, but tends to form dendrites when charged, leading to short circuit. A preliminary anode electrolytic lithiation route has been explored. The carbon sponges were assembled in a coin cell against a lithium metal counter electrode and cycled under galvanostatic conditions. The sponge anode achieved 12 mAh/cm2 charge capacity at 1 mA/cm2 current density without short-circuit. Moreover, the anode displayed outstanding cycle efficiency of 99% for 150 cycles. This preliminary study encouraged us to develop ex-situ sponge-lithiation methods via melt impregnation. The carbon sponge developed by Morrow Batteries (support in the cathode) has been used as a support for Li-metal for use in the anode. The progress on the anode development has been done in collaborations with SINTEF. We advanced a method to deposit Li-metal over the carbon foam for the anode and the major challenge was encountered in developing a reproducible process.

Although, more work needs to be done regarding material/process scale-up to form the basis for production and commercialization of Li-S batteries by Morrow Batteries AS, we have made progress in electrodes developments. One of our R&D achievements obtained within the frame of the project, the impregnation of metallic seed particles during foam manufacture is novel, and if it proves to be beneficial during electrochemical testing would potentially represent new intellectual property.

In this project, Graphene Batteries AS and SINTEF will develop high-performance / low-cost Lithium-Sulphur (LiS) batteries that will support the transition to a carbon-neutral society. Graphene Batteries has already developed a graphene stabilised sulphur cathode based on proprietary technology, that already matches the best state-of-the-art reported in the literature, and it has not yet been optimized. However, in order to produce a battery, an anode and electrolyte compatible with the cathode is needed. Lithium metal has the highest charge density among available anodes, but tends to form dendrites when charged, leading to short circuit. Graphene Batteries has developed a carbon foam to be used as support in the cathode, and this foam will also be used as support for Li-metal for use in the anode. SINTEF will develop a method to deposit Li-metal over the carbon foam for the anode, where carbon will only contribute a few percent to the total mass of the anode. The combined battery will potentially have a practical gravimetric charge density roughly double that of the best Li-ion batteries. Other advantages comprise lower cost of materials, lower environmental impact of production (No use of cobalt or nickel), improved low-temperature performance and reduced risk of thermal run-away safety hazards.