Sputtered Hard Carbon for High-Performance Energy Storage Batteries

Physical vapor deposition produces a range of carbon materials characterized by their diverse microstructure, such as amorphous, granular, and nanocrystalline; by atomic structure graphite-like, and diamond-like which holds varying amounts of carbon aromatic rings and tetrahedral chain structures. From Franklin (1951) to the present day, the hard carbon structure is attributed to multiscale porosity, however, the investigations mostly remained limited to the microscale. The diamond-like carbon (DLC) is an amorphous carbon material that is highly disordered at atomic levels which is composed of a mixture of aromatic rings and chain structure attributing to sp2 and sp3 phases. DLC material has shown its potential to increase retention capacity by 40 % and cycle life by 400 % for lithium batteries [1]. The DLC resembles hard carbon at the atomic scale and plasma-derived hard carbon has demonstrated initial Coulombic efficiency of 88.9 % and rate capacity of 136.6 mAh/g at 5 A/g for sodium-ion batteries [2].
This work demonstrates enhancing Molybdenum Trioxide battery performance with the application of sputtered hard carbon. The hard carbon and Molybdenum Trioxide bilayer material design when tested as a lithium battery anode, has shown a promising capacity of 953 mAhg-1 at a low rate of 0.1C which reduces to 742 mAhg-1 high rate of 1.0C. However, this novel multi-layered structure exhibits exceptional long-term stability with a capacity retention of over 99 % after 3,000 cycles. This proposed materials design opens a pathway for highly efficient and scalable plasma-processed anode materials for next-generation LIBs, SIBs, and beyond.