Hollow-in-Hollow Carbon Spheres for Lithium-ion Batteries with Superior Capacity and Cyclic Performance

•Hollow-in-hollow structured HIHCS was synthesized via a facile templating strategy.•The HCS core and hollow carbon shell constitute the hollow-in-hollow structure.•The HIHCS exhibited superior rate capability and cycle stability as anode material.•The excellent performance is attributed to the unique hollow-in-hollow structure.