Pore Structure Engineering Enables Enhanced Sodium Storage in Boron‐Doped Hard Carbon

Hard carbon (HC) has been considered a promising anode material for sodium‐ion batteries (SIBs). However, a simultaneous regulation strategy to achieve multiscale structure optimization is highly desirable. Herein, we have systematically investigated the effects of pore structure engineering on boron‐doped HC’s microstructure and Na ⁺ storage capability. An appropriate amount of boron atoms incorporated into the carbon matrix leads to the expansion of the closed pores that create more Na ⁺ storage sites, as well as the formation of BC ₃ configurations that enhance Na ⁺ diffusion between adjacent carbon layers, as reported in our previous work. Moreover, the pore‐forming treatment further increased sodium storage active sites such as micropores on the surface of HC without affecting other structure parameters. As a result, the boron‐doped HC anode with optimized pore structure exhibits enhanced rate and cycling performance. In general, this work unravels the critical role of pore structure engineering in optimizing the charge transfer and ion diffusion of boron‐doped HC, which enables rational design of sodium‐ion battery anode with enhanced Na ⁺ storage performance.