Synthesis Of Nanostructured Manganese Oxides And Application In Energy Storage Battery

Lithium-ion batteries?LIBs?dominately hold the energy storage market share for portable electronics and electric vehicles since 1990s,due to their high energy/power density and long cycling life.However,with the rapid development of renewable energy plants,there is an extensive and urgent demand for energy storage technologies for large scale smart grid applications,which require the rechargeable battery systems with good cycling perpormance,low cost,high safety and good environmental friendliness.In searching for new chemistry beyond lithium-ion batteries,the multivalent secondary batteries?Li-S,Zn-Mn,Li-Air,and Zn-Air?have attracted tremendous efforts,which could,in principle,deliver higher energy density based on the multi-elecrtron reaction mechanisms.The development of electrode materials is very important for battery systems.As manganese dioxide?MnO₂?is environmental friendliness,relatively cheap,large abundance and electrochemically active,it is considered as one of the most promising energy storage electrode material.Manganese oxides possess a variety of polymorphs,including?-,?-,?-,?-,?-,and?-type,which show different electrochemical performance.In this paper,we explore the influence of different tunnel sizes?from T[1×1]to T[3×3]?of manganese oxides as host materials for Li-S batteries.Compared with the electrochemical performance of three cathodes in batteries,the larger tunnel size of T[3×3]manganese oxide exhibits the highest initial discharge capacity of 1431.9 mAh?g^-1and maintained a stable cycling performance with over 99%coulombic efficiency at 1 C over 300 cycles.Next,we find a new materials of hollow MnO₂ nanospheres which can be used for aqueous Zn-Mn O₂ batteries.The hollow MnO₂ nanospheres can achieve high specific capacity up to⁴05 mAh?g^-11 at 0.5 C.Notably,after 100 cycles,the discharge capacity was stabilized at³05 mAh?g^-1 with a coulombic efficiency over 97%.