As the widespread emergence of modern technologies combined with human life, lithium ion battery (LIBs) has become one of the most important power supplier for mobile electronic devices, electric vehicles and stationary applications. However, the current LIBs provide a low energy density with approaching to the capacity limits, which emphasize the urgent need for high energy density battery systems.

Herein, we have prepared the amorphous silicon nanolayer-embedded graphite/carbon (SGC) hybrids by chemical vapor deposition (CVD) method with developing the cost-effective and scalable pyrolysis system. With developing an industrial-relevant modified CVD process, sophisticated structure of optimum SGC hybrids achieved high reversible capacity (523 mAh g-1) and unprecedented coloumbic efficiency (92%) at a 1^st cycle in the industrial standard electrode density (> 1.6 g cc^-1) and areal capacity loading of > 3.3 mAh cm^-2. Moreover, fabricated SGC electrode confirmed rapid increase of cycling efficiency upward of 99.5% over only 6^th cycles and exactly allowed favorable cyclability of 96% capacity retention after 100 cycles and high rate capability comparable to the industrial graphite anode. In addition, the electrode composed of SGC hybrids entirely overcame the detrimental effects of the volume variation problems, exhibiting 23% of additional expansion excepting for graphite counterpart. This, in turn, completely preserved the electrical interconnectivity and mechanical integrity without any cracks and contact losses. Finally, a prototype full cell device is demonstrated with high voltage lithium cobalt oxide (LCO) cathode through the coin cell configuration, which achieved 92% of capacity retention after 100 cycles with considerable potential toward next generation target as practical devices. Consequently, this successful SGC hybrid anodes could be proposed for commercial extension to the next generation high-energy battery systems as a major breakthrough for electric vehicle or grid energy storage applications.

Scheme 1. Schematic of fabrication process for SGC hybrids. Gas phase of Silane (SiH₄) can easily adsorb and penetrate on a pristine graphite (PG), which leads to homogeneous and highly pure amorphous silicon nanolayer coating on both inner and outer surface of PG as silicon graphite (SG) hybrids. In the end, SGC hybrids are invented from SG through carbon coating with acetylene (C₂H₂) gas by CVD method.