Manganese oxides(MnOx)have been exten-sively investigated due to their extremely high theoretical capacities for application as conversion anodes in lithium-ion batteries.However,fully performing their theoretical performance still faces poor electric conductivity and serious volume change upon lithium insertion/extraction.Herein,we demonstrate encapsulating manganese oxide nanoparticles within a conducting polymer polypyrrole(PPy)shell as a facile strategy to overcome such flaws through in situ redox reaction and oxidative polymerization process.Such an in situ method combines the redox reac-tion between potassium permanganate and tetrahydrofuran to form MnOx nanoparticles and the subsequent oxidative polymerization of pyrrole to form a conductive polypyrrole coating shell by the oxidant KMnO4 into one step.For the as-fabricated products(MnOx@PPy),this tenderly intro-duced conductive PPy shell highly favors the fast electron transfer and preserves the electrode structure integrity upon repeated cycling.As the anode for LIBs,MnOx@PPy exhibits superior lithium storage performance with a high reversible capacity(1538 mAh·g-1),long-life cyclability(747 mAh·g-1 after 1000 cycles at 1.0C)and durable ratability(574 mAh·g-1 at 2.0C).This work demonstrates that the convenient in situ strategy to form conductive polymer coating shell is effective to improve the perfor-mance of conversion anodes and can be extended to other materials for energy storage applications.