A high-capacity, low-cost phosphorus anode is considered as one of the most promising candidates for next-generation Li-ion batteries. Nevertheless, the dissolution/shuttle effect of lithium polyphosphides and sluggish electrochemical conversion hinder the practical application of a phosphorus anode, similar to the problems of a sulfur cathode. Although the reported functional additives with physical obstruction and chemical adsorption have been successful in improving the performance of a sulfur cathode, they can not be directly applied to phosphorus due to their deterioration and failure in low voltage. To solve the above problems, we made a systematic investigation to rationally select the functional additives (Li2O, Li2S, and LiF) and effectively guide the experiment. These functional additives possess synergetic effects, including the adsorption of soluble lithium polyphosphides and the catalytic conversion of phosphorus species. The design of these functional additives provides a guiding and screening principle for inhibiting the dissolution of polyphosphides and improving the reaction kinetics of a phosphorus anode.