Dual-confined SiO encapsulated in PVA derived carbon layer and chitin derived N-doped carbon nanosheets for high-performance lithium storage

Abstract

• A facile process is developed to prepare biomass chitin derived SiO x /C for LIBs. • The exfoliated 2D chitin nanosheet and PVA are utilized to confine SiO x , which maintain structure integrity after carbonization. • The dual-confining SiO x in 2D carbon nanosheet shows significantly enhanced capacity and cycling performance. • A full cell using LiCoO 2 -SiO x /C is successfully built to demonstrate the application and performance of the newly designed anode material. SiO x anodes hold great promise for next-generation lithium-ion batteries (LIBs) due to the high capacity and enhanced cycling stability versus silicon. However, its long-term development is hampered by seeking a scalable and effective method to tackle the issues of low conductivity and large volume expansion. Herein, a novel anode material is constructed by wrapping SiO x into PVA derived carbon layer and N-doped carbon (NC) nanosheets derived from exfoliated chitin nanosheets. The SiO x nanoparticles tightly encapsulated by the chitin nanosheets and PVA are transformed to robust SiO x @NC composites after pyrolysis. The encapsulation of PVA derived carbon layer and the NC sheets enhances the conductivity, relieves the volume change, and contributes to forming a stable SEI film. As a result, the prepared SiO x @NC-2 anode delivers a stable cycling performance and competitive rate capability. After 300 cycles at 0.5 A g −1 , a relatively high capacity of 602 mA h g −1 is maintained. The cost-effective precursors and facile synthetic route can promote the application of the SiO x @NC composites as anode materials in energy storage, as well as facilitating the large-scale application of the biowaste derived chitin.