Recent Advances in Rational Electrode Designs for High‐Performance Alkaline Rechargeable Batteries

Abstract

In recent years, noticeable progress is achieved regarding alkaline rechargeable batteries (ARBs). Due to their merits of safety and low cost, ARBs are considered promising energy storage sources for large-scale grid energy storage, electric vehicles, and hybrid electric vehicles, as well as wearable and portable devices. While previous reviews have focused on specific topics associated with ARBs, providing a comprehensive review on rechargeable alkaline batteries is both timely and worthwhile. In this review, the recent progress in ARBs is summarized and the strategies underlying rational electrode designs for cathodes and anodes are highlighted, as well as their applications in full cells including flexible batteries. This review may pave the way for further designs of high-performance alkaline batteries. and a LiMn 2 O 4 cathode in 1994. [10] However, the electrolyzation of H 2 O limits the operating voltage window of ARABs, which are stable within ≈1.23 V. Furthermore, the electrode materials should be selected so that they avoid the electrolysis of H 2 O and maintain chemical stability in H 2 O. [3a] However, the preferred LIB cathodes, such as LiCoO 2 , LiMn 2 O 4 , and LiFePO 4 , which display a reversible capacity of 140, [11] 120, [12] and 170 mAh g −1 , [13] respectively, exhibit narrow working potentials and high stability in aqueous solutions but can take part in one-electron reactions at most. In addition, promising anode materials, such as VO 2 , [14] V 2 O 5 , [15] and H 2 V 3 O 8 , [16] possess the theoretical capacity or show the highest reversible capacity of only 161.6, 200, and 234 mAh g −1 , respectively, [3a] thereby leading to a full cell with a low energy density under the limited operating voltage window in aqueous electrolytes. Although the so-called "water-in-salt" electrolyte and its many variations can enable aqueous batteries with an electrochemical stability window of >3.0 V and an energy density of 200 Wh kg −1 , respectively, the ultrahighly concentrated electrolyte makes the cost too high for practical applications. [17] Since the early 20th century, alkaline rechargeable batteries (ARBs) based on nickel-iron (Ni-Fe) and nickel-cadmium (Ni-Cd) have been established and developed by Jüngner and Edison. [18] These batteries, which use alkaline solution as electrolytes, undergo an entirely different storage mechanism from ARABs and involve H + insertion/extraction and conversion processes from the alkali-metal ion insertion/extraction. Take the reaction mechanism of Ni-Fe batteries as an example

Toward Promising Cathode Catalysts for Nonlithium Metal–Oxygen Batteries

“…Energy Mater. 2020, 10,1901997 respectively. Subsequently, by dividing f G ∆ Θ with the total weight/volume of the reactions, theoretical gravimetric/ volumetric energy densities can be obtained.…”

“…Energy Mater. 2020, 10,1901997 Reproduced with permission. [107] Copyright 2016, Wiley-VCH; b) discharge profile and power density of a Zn-O 2 battery using the Fe-N-C catalyst; c) photo of an LED screen powered by the Zn-O 2 batteries with this air cathode catalyst.…”

“…The limited energy density of LIBs (≈400 Wh kg −1 ) and their unsatisfying safety, unfortunately, are the major challenges for further expanding their practical application in the various potential fields, such as electric vehicles (EVs) with a long driving range . Even though the energy density can be considerably enhanced by replacing the current Li‐ion configuration into a Li–O 2 configuration that directly utilizes lithium metal and oxygen gas as the anode and cathode active species, there is still no doubt that the safety and cost issues can hardly be overcome due to the unavoidable involvement of scarce metallic lithium in these Li‐based battery chemistries . Therefore, alternative nonlithium metal–air batteries (e.g., Zn–O 2 and Al–O 2 batteries) with cheaper metal anodes (e.g., Na, K, Zn, Mg, and Al) have been believed to possess a better potential for powering long service portable devices and high‐mileage EVs, regarding their more satisfying price‐quality ratios and much improved safety .…”

“…[1][2][3][4][5][6][7][8][9] Even though the energy density can be considerably enhanced by replacing the current Li-ion configuration into a Li-O 2 configuration that directly utilizes lithium metal and oxygen gas as the anode and cathode active species, there is still no doubt that the safety and cost issues can hardly be overcome due to the unavoidable involvement of scarce metallic lithium in these Li-based battery chemistries. [10] Therefore, alternative nonlithium metal-air batteries (e.g., Zn-O 2 and Al-O 2 batteries) with cheaper metal anodes (e.g., Na, K, Zn, Mg, and Al) have been believed to possess a better potential for powering long service portable devices and high-mileage EVs, regarding their more satisfying price-quality ratios and much improved safety. [11][12][13][14][15] Compared with LIBs, the commercialization future of non-Li metal-O 2 batteries is still vague, which is primarily due to the slow intrinsic reaction kinetics, the high overpotentials, and the low round-trip efficiency of the oxygen redox chemistry in these batteries.…”

Zinc Ferrite Nanorod‐Assembled Mesoporous Microspheres as Advanced Anode Materials for Sodium‐Ion Batteries

“…In search of potential SIB anodes, various micro-or nano-structured materials have been developed extensively. [5][6][7][8][9][10][11][12][13] According to the differences of their sodium storage mechanisms, the currently developed anodes can be mainly classified into four categories containing insertion-type, alloy-type, organic-type, and conversion-type materials. [14][15][16][17][18][19][20][21][22] Among them, conversion-type materials are attractive anodes due to their diverse compositions with high theoretical sodium-storage capacities.…”