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

SiOx 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 SiOx into PVA derived carbon layer and N-doped carbon (NC) nanosheets derived from exfoliated chitin nanosheets. The SiOx nanoparticles tightly encapsulated by the chitin nanosheets and PVA are transformed to robust SiOx@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 SiOx@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 SiOx@NC composites as anode materials in energy storage, as well as facilitating the large-scale application of the biowaste derived chitin.