Superior-Performance Aqueous Zinc-Ion Batteries Based on the In Situ Growth of MnO₂ Nanosheets on V₂CT_X MXene

Abstract

Mn-based aqueous zinc-ion batteries (ZIBs) are promising candidate for large-scale rechargeable energy storage because of easy fabrication, low cost, and high safety. Nevertheless, the commercial application of Mn-based cathode is hindered by the challenging issues of low rate capability and poor cyclability. Herein, a manganese–vanadium hybrid, K–V2C@MnO2 cathode, featured with MnO2 nanosheets uniformly formed on a V2CTX MXene surface, is elaborately designed and synthesized by metal–cation intercalation and following in situ growth strategy. Benefiting from the hybrid structure with high conductivity, abundant active sites, and the synergistic reaction of Mn2+ electrodeposition and inhibited structural damage of MnO2, K–V2C@MnO2 shows excellent electrochemical performance for aqueous ZIBs. Specifically, it presents the high specific capacity of 408.1 mAh g–1 at 0.3 A g–1 and maintains the specific capacity of 119.2 mAh g–1 at a high current density of 10 A g–1 in a long-term cycle of up to 10000 cycles. It is superior to almost all reported Mn-based cathodes for ZIBs in the aqueous electrolyte. The superior electrochemical performance suggests that the Mn-based cathode materials designed in this work can be a rational approach to be applied for high-performance ZIBs cathodes.

Hierarchical K‐Birnessite‐MnO2 Carbon Framework for High‐Energy‐Density and Durable Aqueous Zinc‐Ion Battery

“…It is almost the most exciting electrochemical performance among the reported work as shown in Figure 4e [16,18,25,31,33,47,[58][59][60][61] and Table S4 (Supporting Information). The long-term cycling stability performance of KMO, CNT@KMO, and CNT@KMO@ GC was also evaluated.…”

“…d) The relationship between time and potential of CNT@KMO@GC-based battery at different current densities. e) The comparison of rate performance of CNT@KMO@GC-based battery with the reported aqueous ZIBs, including A: K-V 2 C@MnO 2 , [18] B: O d -K 0.27 MnO 2 , [59] C: MnO 2 /rGO, [33] D: CNT@a-MnO 2 , [60] E: O d -MnO 2 , [61] F: Na 0.23 MnO 2 , [16] G: Ca 0.28 MnO 2 , [25] H: CNF@MnO 2 , [31] I: N-CNS@MnO 2 , [47] and J: PANI-MnO 2 . [58] f) Long-term cycling stability performance of KMO-, CNT@KMO-, and CNT@KMO@GC-based batteries at 5.0 A g −1 .…”

“…The investigation yields consensus of MnO 2 as the most prevalent choice thanks to its good economy, low toxicity, high theoretical capacity, and working potential. [5,10,[16][17][18] However, the low electronic/ionic conductivity and non-negligible manganese dissolution of MnO 2 result in the inferior rate performance and fast capacity decay of MnO 2 -based cathodes, hindering the commercialization of ZIBs. [19][20][21] Great endeavors have been dedicated to improve the reaction kinetics and structural stability of MnO 2 -based cathodes in strategies of polymorphs regulation, [16,22] preintercalation, [18,[23][24][25][26][27][28] heteroatom doping, [29,30] compositing with conductive materials, [18,[31][32][33][34][35] and Mn 2+ additives of electrolyte.…”

“…[5,10,[16][17][18] However, the low electronic/ionic conductivity and non-negligible manganese dissolution of MnO 2 result in the inferior rate performance and fast capacity decay of MnO 2 -based cathodes, hindering the commercialization of ZIBs. [19][20][21] Great endeavors have been dedicated to improve the reaction kinetics and structural stability of MnO 2 -based cathodes in strategies of polymorphs regulation, [16,22] preintercalation, [18,[23][24][25][26][27][28] heteroatom doping, [29,30] compositing with conductive materials, [18,[31][32][33][34][35] and Mn 2+ additives of electrolyte. [9,36] All these strategies have been proven to effectively improve the electrochemical performance of MnO 2 -based cathodes in ZIBs to some extent.…”

“…[5,16] Both preintercalation of guest species into MnO 2 and compositing MnO 2 with electrical conductive materials can improve its electrical conductivity, suppress manganese dissolution, and stabilize its structure. [18,21,25,28,34] Moreover, there are also considerable attempts to reveal the charge storage mechanism of aqueous mild Zn-MnO 2 batteries with the aim of further performance optimization. [5] Different energy storage mechanisms, such as Zn 2+ insertion/extraction, [35] H + /Zn 2+ coinsertion, [37] conversion reaction, [9] and dissolution/deposition, [38] have been proposed to explain certain ZIBs systems.…”