Si monoxide and its suboxides (SiOx) are promising anode materials for lithium-ion batteries which have attracted special attention recently due to its high specific capacity and improved cycling performance, with some similarities to Si anodes. While Li oxide (Li2O) and Li silicates (Li4SiO4), generated by the reaction of Li ion with SiOx during the first lithiation process lowers the theoretical capacity, they also act as buffer components to accommodate volume changes caused by further reactions between Si in SiOx with Li, leading to improved cyclability. One of the main drawbacks of this material is the low first cycle Coulombic efficiency due to the formation of the Li oxide and Li silicates. In this paper, the electrochemical properties and related mechanism of SiOx are reviewed. The current research progress to enhance SiOx electrochemical performance by nanostructuring and the effect of other battery components such as binders, electrolyte, and prelithiation on its electrochemical performance is also discussed. Finally, potential research directions and strategies to further improve the performance of SiOx are also briefly discussed and suggested.