Graphene-oxide-templated P/S-codoped hard carbon with a coral-like layered architecture for pseudocapacitance-boosted sodium storage

This is the authors' abstract. We don't add key points for this paper.

Facing lithium resource and cost bottlenecks, low-cost and abundant sodium-ion batteries provide an attractive complement for grid storage. However, graphite anodes cannot accommodate rapid Na⁺ insertion because of their narrow interlayer spacing. Here, inspired by the layered architecture of coral polyps, we construct a flex–hard carbon architecture consisting of an outer phenolic-resin-derived hard carbon layer and an inner graphene oxide (GO)-derived carbon framework. GO acts as a two-dimensional template and conductive support, while P/S codoping modifies the surface composition and carbon structure, resulting in P/S-rGO@C. This architecture integrates accessible sodium-storage sites with a conductive carbon framework. P/S-rGO@C delivers 311 mAh g−1 at 0.1 A g−1, retains 152.1 mAh g−1 at 10 A g−1, and sustains 206.6 mAh g−1 over 1000 cycles at 3 A g−1. Electrochemical analyses reveal that the improved sodium-storage performance is associated with the combined effects of surface chemical composition and carbon architecture. This coral-inspired design provides a strategy for developing high-rate and durable sodium-ion anodes. Sodium-ion batteries are a low-cost option for grid storage, but graphite anodes limit fast Na⁺ storage. Here, the authors developed a coral-inspired P/S-codoped carbon anode that achieves high-capacity, fast-charging, and durable sodium storage through synergistic structural and surface engineering.