Honeycomb in honeycomb carbon bubbles: excellent Li- and Na-storage performances

Abstract

Herein, honeycomb in honeycomb carbon bubbles (HHCBs) with macro-, meso-, micro-, and nanopores have been successfully obtained for the first time via a simple one-step direct templating method. Benefiting from unique features, the HHCBs demonstrate superior cycling stability and rate capability when employed as anode materials for both lithium and sodium-based batteries. For instance, hollow carbon bubbles used as lithium ion battery anodes deliver a high reversible capacity of 1583 mA h g⁻¹ and nearly 100% capacity retention over 100 cycles at a constant current of 372 mA g⁻¹ (1C). A high reversible capacity of 200 mA h g⁻¹ also can be obtained at an extremely high current rate of 300C. When tested as sodium ion battery anodes, the electrode can deliver an initial reversible capacity of 373 mA h g⁻¹ and retain 209 mA h g⁻¹ after 400 cycles at 100 mA g⁻¹. Even at a high current rate of 1000 mA g⁻¹, the electrode still can release a substantial reversible capacity of 122 mA h g⁻¹ after discharging–charging for 700 cycles, suggesting a high rate capability and cyclability. The approach provides a valuable candidate acceptable for use as both lithium and sodium ion battery anodes.