Recent advances and perspectives of microsized alloying-type porous anode materials in high-performance Li- and Na-ion batteries

Alloying materials (e.g., Si, Ge, Sn, Sb, and so on) are promising anode materials for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to their high capacity, suitable working voltage, earth abundance, environmental friendliness, and non-toxicity. Although some important breakthroughs have been reported recently for these materials, their dramatic volume change during alloying/dealloying causes severe pulverization, leading to poor cycling stability and safety risks. Although the nanoengineering of alloys can mitigate the volumetric expansion to some extent, there remain other drawbacks, such as low initial Columbic efficiency and volumetric energy density. Porous microscale alloys comprised of nanoparticles and nanopores inherit micro- and nanoproperties, so that volume expansion during lithiation/sodiation can be better accommodated by the porous structure to consequently release stress and improve the cycling stability. Herein, the recent progress of porous microscale alloying-type anode materials for LIBs and SIBs is reviewed by summarizing the Li and Na storage mechanisms, the challenges associated with different materials, common fabrication methods, and the relationship between the structure and electrochemical properties in LIBs and SIBs. Finally, the prospects of porous microscale alloys are discussed to provide guidance for future research and the commercial development of anode materials for LIBs and SIBs.