Alloying materials, recognized as promising candidates for graphite anodes, are extensively explored for their high energy densities. However, the chronic challenges originating from volumetric expansion and the resultant stress leading to particle fracture have impeded the practical application of these materials in alkali ion batteries. Beginning with the fundamental thermodynamics of alloying materials, this review investigates their detailed electrochemical reactions and examines how these reactions can affect battery performance from both mechanical and electrochemical perspectives. Moreover, key parameters governing the reaction mechanisms are elucidated, followed by engineering strategies that alter the behavior of alloying reactions. This review will suggest guidelines for designing alloying anodes to enhance battery performance.