Nano-spring confined in a shrinkable graphene cage towards self-adaptable high-capacity anodes

High-capacity Li-ion battery anode materials, normally coated with carbons, suffer from the issue of mismatch between the dynamic noncarbon cores and the static carbon shells upon lithiation and de-lithiation. Here, we build a self-adaptable electrical and mechanical carbon network by embedding the carbon nanotubes into a capillary-shrinking graphene hydrogel forming nano-springs to robustly connect and buffer the active non carbon nanoparticles. This produced dense carbon cage can buffer the volume fluctuations of noncarbons and simultaneously retain a dynamic electrical connectivity with expanding/contracting noncarbon nanoparticles during charging and discharging. With this self-adaptable carbon structure for noncarbon nanoparticles (typically the tin oxide and silicon), high volumetric capacities (up to 1920 mAh cm-3) together with long cycle life (up to 600 cycles) and very limited electrode expansion are achieved in the nanosized yet compact noncarbon anode.

Automated summary

By embedding carbon nanotubes into a graphene hydrogel, a self-adaptable carbon network is built to buffer the volume fluctuations of noncarbon nanoparticles and maintain dynamic electrical connectivity during charging and discharging. This structure enables the noncarbon anode to achieve high volumetric capacities and long cycle life.