Challenges and perspectives for manganese‐based oxides for advanced aqueous zinc‐ion batteries

Abstract

Li‐ion batteries (LIBs) with excellent cycling stability and high‐energy densities have already occupied the commercial rechargeable battery market. Unfortunately, the high cost and intrinsic insecurity induced by organic electrolyte severely hinder their applications in large‐scale energy storage. In contrast, aqueous Zn‐ion batteries (ZIBs) are being developed as an ideal candidate because of their cheapness and high security. Benefiting from high operating voltage and acceptable specific capacity, recently, manganese‐based oxides with different various crystal structures have been extensively studied as cathode materials for aqueous ZIBs. This review presents research progress of manganese‐based cathodes in aqueous ZIBs, including various manganese‐based oxides and their zinc storage mechanisms. In addition, we also discuss some optimization strategies that aim at improving the electrochemical performance of manganese‐based cathodes, and the design of flexible aqueous ZIBs based on manganese‐based cathodes (MZIBs). Finally, this review summarizes some valuable research directions, which will promote the further development of aqueous MZIBs.

High-Voltage Flexible Aqueous Zn-Ion Battery with Extremely Low Dropout Voltage and Super-Flat Platform

“…a pair of strong redox peaks located around 1.6/2.2 V was observed, which was correlated with the conversion of [Fe III (CN) 6 ] 3− ↔[Fe II (CN) 6 ]4 and Zn ↔ Zn 2+ . During the cathodic process, the distinct reduction peak around 1.57 V (scan rate of 10 mV s −1 ) was related to the transformation of [Fe III (CN) 6 ] 3− to [Fe II (CN) 6 ] 4− and the Zn dissolution.…”

“…With the increasing demand for flexible electronic devices such as smart bracelet, flexible sensor, and smart clothing, more stringent requirements are raised for the energy storage devices including high voltage, high energy density, environmental friendliness, favorable mechanical property, etc. [1][2][3][4][5]. Although commercial lithium-ion batteries are the mainstream power source in the energy storage market, their visible defects such as the restrictive lithium resources, complicated assembly process, and especially for the toxic organic electrolytes, prevent their further wide application in the smart and wearable electronics [6][7][8][9][10][11].…”

Defect Engineering in Manganese‐Based Oxides for Aqueous Rechargeable Zinc‐Ion Batteries: A Review

“…These various polymorphs have been investigated as cathode materials for ZIBs. [ 28,29 ] Other than these common MnO 2 polymorphs, other manganese‐based oxides, such as MnO, Mn 2 O 3 , Mn 3 O 4 , LiMn 2 O 4 , KMn 8 O 16 , Na 2 Mn 3 O 7 , ZnMn 2 O 4 , and MgMn 2 O 4 have been explored as potential cathode materials for ZIB. [ 46–52 ] The reaction mechanisms for these manganese‐based oxides are summarized in Figure 3 .…”

“…To date, the most widely reported cathode materials are vanadium‐based materials, [ 26,27 ] manganese‐based materials, [ 28,29 ] Prussian blue analogues, [ 30,31 ] and, to a small extent, metal chalcogenides such as MoS 2 . [ 32–34 ] Among which, manganese‐based materials are highly favored for its highly matured synthesis techniques, low cost, and its wide range of polymorphs.…”

Mild‐Temperature Solution‐Assisted Encapsulation of Phosphorus into ZIF‐8 Derived Porous Carbon as Lithium‐Ion Battery Anode

“…Furthermore, the specific capacity attenuation was about 0.04% per cycle at 1 A g −1 within 700 cycles after ten cycles of activation, demonstrating the good cycling stability of ZIF‐8‐C@PP anode. (Figure 4f) Overall, the unique features of ZIF‐8‐C@PP may shed a bright future for large‐scale energy storage due to its excellent battery performance: [ 37–46 ] first, ZIF‐8‐C@PP has a high phosphorous content of 30 wt% and nearly no crystalline RP formed on the outer surface attributing to the solution‐based phosphorous encapsulation method thus enhancing the utilization of phosphorus and ensuring a large specific capacity for ZIF‐8‐C@PP; second, the pores in ZIF‐8‐C hosts physically confined the expansion of phosphorus and incompletely filled pores provided buffer space during volume expansion.…”