A Universal Principle to Design Reversible Aqueous Batteries Based on Deposition–Dissolution Mechanism

Abstract

cations), [1] as well as novel electrolytes with broadened electrochemical stability window such as the water-in-salt electrolytes. [2] Comprehending battery chemistries enlightened to battery performance improvement, which could be classified into two typical charge storage mechanisms for electrode materials, namely, insertion/extraction mechanism and chemical conversion mechanism. Thus, as for a full aqueous battery, three dominated working principles can be identified based on the reactions occurred in electrode materials. Specifically, the first is the rocking-chair type that both cathode and anode materials provide intercalation channels for ions, such as alkaline cation batteries. [1a,2a,3] The second is a mixed process, such as newly reported Zn 0.25 V 2 O 5 -Zn and LiMn 2 O 4 -Zn batteries, in which ions intercalation happens in cathode (Zn 2+ inserted into Zn 0.25 V 2 O 5 , Li + into LiMn 2 O 4 ) and the conversion reaction dominates in the counterpart anode (plating-stripping of Zn). [1c,d,2b] However, the third working principle, of which chemical conversion reactions proceed in both cathode and anode materials for aqueous batteries, has been scarcely explored, only including traditional leadacid batteries [4] and sporadic examples. [1b,5] Nevertheless, it is inspiring that the battery performance based on chemical conversion mechanism exhibits outstanding performance, such as high voltage, large capacity, and stable cyclability. [1b,4a,5,6] Thus, adopting conversion mechanism on both electrodes may open a new door to improve aqueous battery performance and it is of large potential to broaden the selection spectrum of electrode materials and electrolytes. However, to our knowledge, there is no systematic methodology to design batteries based on conversion reactions for both electrodes and the corresponding chemistry is far from being well understood.Electrodeposition is a powerful and versatile theme in electrochemistry, which enables diversified applications, such as materials synthesis and anticorrosive coating, by in situ synthesis of insoluble deposits at solid-liquid heterogeneous interfaces. [7] The deposition reactions can be triggered on specific conditions, kinetically and thermodynamically, including externally applied potentials, pH, temperature, and ion concentration variations. Various species, such as metals or metal Conventional charge storage mechanisms for electrode materials are common in widely exploited insertion/extraction processes, while some sporadic examples of chemical conversion mechanisms exist. It is perceived to be of huge potential, but it is quite challenging to develop new battery chemistry to promote battery performance. Here, an initiating and holistic deposition-dissolution battery mechanism for both cathodes and anodes is reported. A MnO 2 -Cu battery based on this mechanism demonstrates outstanding energy density (27.7 mWh cm −2 ), power density (1232 mW cm −2 ), high reversibility, and unusual Coulombic efficiency. It can be charged to 0.8 mAh cm −2 within 42...

A High Energy Density Aqueous Battery Achieved by Dual Dissolution/Deposition Reactions Separated in Acid‐Alkaline Electrolyte

“…It needs to point out that the CE is larger than 100% at around 200–400 cycles, which is due to the accumulation of MnO 2 in the initial cycles as seen in Figure S9 of the Supporting Information. Similar phenomenon was also observed in Zhi's work …”

Low-cost and high safe manganese-based aqueous battery for grid energy storage and conversion

“…2b), showing an excellent cyclic stability (which is five times longer than 2000 cycles under 0.8 mAh cm À2 capacity reported in Ref. [33]). When charged with the higher deposition capacities of 10 and 30 mAh cm À2 , the Cu-Mn cells also keep very stable discharge capacity during 1000 and 500 cycles ( Fig.…”

“…Replacing the hydrogen with metal electrode (such as Cu) to form metal-manganese battery might be a practicable idea, which has been patented by our group in 2018 [31]. Very recently, several groups investigated this Cu-Mn battery [32,33]. However, the achieved performances, such as the low areal capacity (<1 mAh cm À2 ) and limited cycle life (<2000 cycles), are still far away from practical application.…”

Initiating Hexagonal MoO3 for Superb‐Stable and Fast NH4+ Storage Based on Hydrogen Bond Chemistry

“…[ 1,10 ] Additionally, the intrinsic safety of aqueous battery and the earth abundant elements of nonmetallic charge carrier would serve as a competitive energy storage candidate to meet safe and cheap application requirements, such as newly‐boosting wearable and flexible battery, grid‐level stationary application. [ 6,11,12 ] Thus, inspired by the outstanding performance, it is promising to develop batteries based on charge carriers as nonmetallic cations.…”