Alloying and conversion‐based anodes promise gravimetric capacities beyond graphite and hard carbon in alkali (Li‐, Na‐, and K)‐ion batteries (AIBs). Sn 4 P 3 is an emerging high‐capacity mixed conversion‐alloying anode for AIBs, despite its huge volume changes, irreversibility issues, and interphase instability during long‐term cycling. The recent advances of this high‐capacity anode material span across understanding the reaction mechanism via operando and computational insights, implementing nanostructuring, constructing rational carbon, and other inorganic composite architectures, engineering the electrode–electrolyte interphase, altering the electrode design, and testing parameters to address the challenges in achieving reversible capacity and long‐term cyclability. Additionally, we highlight the key areas such as origin of low initial Coulombic efficiency, large volumetric strain, and kinetic hysteresis in AIBs (particularly for Na/K‐ion systems), where more fundamental studies are necessary and outline research directions to achieve practical Sn 4 P 3 anodes with long‐term cyclability.
Haridas et al. (Sun,) studied this question.