Manganese oxides(MnO_(x)) have been extensively investigated due to their extremely high theoretical capacities for application as conversion anodes in lithiumion batteries. However, fully performing their theoretical...Manganese oxides(MnO_(x)) have been extensively investigated due to their extremely high theoretical capacities for application as conversion anodes in lithiumion 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 reaction between potassium permanganate and tetrahydrofuran to form MnO_(x)nanoparticles and the subsequent oxidative polymerization of pyrrole to form a conductive polypyrrole coating shell by the oxidant KMnO_(4) into one step. For the as-fabricated products(MnO_(x)@PPy), this tenderly introduced conductive PPy shell highly favors the fast electron transfer and preserves the electrode structure integrity upon repeated cycling. As the anode for LIBs, MnO_(x)@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 1.0 C) and durable ratability(574 mAh·g^(-1) at 2.0 C). This work demonstrates that the convenient in situ strategy to form conductive polymer coating shell is effective to improve the performance of conversion anodes and can be extended to other materials for energy storage applications.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51702346 and 51772314)the Natural Science Foundation of Shanghai(No.17ZR1434600)Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(No.19DZ2290700)。
文摘Manganese oxides(MnO_(x)) have been extensively investigated due to their extremely high theoretical capacities for application as conversion anodes in lithiumion 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 reaction between potassium permanganate and tetrahydrofuran to form MnO_(x)nanoparticles and the subsequent oxidative polymerization of pyrrole to form a conductive polypyrrole coating shell by the oxidant KMnO_(4) into one step. For the as-fabricated products(MnO_(x)@PPy), this tenderly introduced conductive PPy shell highly favors the fast electron transfer and preserves the electrode structure integrity upon repeated cycling. As the anode for LIBs, MnO_(x)@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 1.0 C) and durable ratability(574 mAh·g^(-1) at 2.0 C). This work demonstrates that the convenient in situ strategy to form conductive polymer coating shell is effective to improve the performance of conversion anodes and can be extended to other materials for energy storage applications.
