Low-Temperature Reduction Strategy Synthesized Si/Ti_3C_2 MXene Composite Anodes for High-Performance Li-Ion Batteries

摘要

Silicon is attracting enormous attention due to its theoretical capacity of 4200 mAh g(-1) as an anode for Li-ion batteries (LIBs). It is of fundamental importance and challenge to develop low-temperature reaction route to controllably synthesize Si/Ti3C2 MXene LIBs anodes. Herein, a novel and efficient strategy integrating in situ orthosilicate hydrolysis and a low-temperature reduction process to synthesize Si/Ti3C2 MXene composites is reported. The hydrolysis of tetraethyl orthosilicate leads to homogenous nucleation and growth of SiO2 nanoparticles on the surface of Ti3C2 MXene. Subsequently, SiO2 nanoparticles are reduced to Si via a low-temperature (200 degrees C) reduction route. Importantly, Ti3C2 MXene not only provides fast transfer channels for Li+ and electrons, but also relieves volume expansion of Si during cycling. Moreover, the characteristics of excellent pseudocapacitive performance and high conductivity of Ti3C2 MXene can synergistically contribute to the enhancement of energy storage performance. As expected, Ti3C2/Si anode exhibits an outstanding specific capacity of 1849 mAh g(-1) at 100 mA g(-1), even retaining 956 mAh g(-1) at 1 A g(-1). The low-temperature synthetic route to Si/Ti3C2 MXene electrodes and involved battery-capacitive dual-model energy storage mechanism has potential in the design of novel high-performance electrodes for energy storage devices.