Prelithiation of silicon encapsulated in MOF-derived carbon/ZnO framework for high-performance lithium-ion battery

Silicon possesses a high theoretical capacity, making it a potential contender for lithium-ion battery (LIB) anodes. Nonetheless, its practical usage is challenged by low electrical conductivity and significant volume expansion during cycling. Here, we synthesized a novel silicon/carbon (Si/C) anode doped with ZnO via a template-derived method and high-temperature carbonization. The carbon structure, originated from metal-organic frameworks (MOFs) and ZnO doping, substantially enhanced the electrochemical properties of the composite material. It exhibited an initial capacity of 2 100.3 ​mA ​h ​g −1 at a current density of 0.2 ​A ​g −1 and demonstrated excellent capacity retention over successive cycles. Moreover, the composite material displayed superior rate performance at higher current densities of 2 A ​g −1 and 3 ​A ​g −1 . To address the low initial Coulombic efficiency (ICE) of silicon-based materials, we adopted a direct contact prelithiation approach and optimized the lithiation process by controlling the prelithiation time. After 30 ​min of prelithiation, the ICE reached 97.9 ​%, thereby reducing the initial irreversible capacity loss (ICL) and realizing stable discharge-charge in subsequent cycles. This rational design provides valuable insights for achieving high-performance silicon anode.