Concave Engineering of Hollow Carbon Spheres toward Advanced Anode Material for Sodium/Potassium-Ion Batteries

摘要

Concave carbon spheres have attracted enormous interest due to their uniquephysicochemical properties. However, the precise synthetic methodology isstill scarce, because it is a great challenge to control the dynamic and nonselectivedeformation process of the intermediate precursor. Herein, a seriesof hollow carbon spheres with tunable concavity are prepared by a facileand efficient polymerization-buckling strategy. Both the concave degree andconcave density of these hollow carbon spheres can be precisely regulated.Finite element analysis indicates the unique concave morphology can relievethe stress accumulation during the cycling process, endowing concave hollowcarbon spheres with superior potassium and sodium storage performance.As the anode for potassium-ion batteries, stable capacity of 104.9 mAh g~(?1) canbe achieved at 4 A g~(?1) after 1350 cycles. For sodium-ion batteries, reversiblecapacity of 116.4 mAh g~(?1) after 2700 cycles can be enabled at 2 A g~(?1). Thiswork may open a new avenue for the design of concave hollow carbon materialsand promote their practical application in energy storage field.