Research Progress for the Development of Li‐Air Batteries: Addressing Parasitic Reactions Arising from Air Composition

Abstract

Green and renewable resources are more attractive than nonrenewable energy sources, which have been significantly exhausted. In addition, the rapid consumption of nonrenewable fossil fuels will result in the accumulation of CO 2 in the atmosphere and other serious environmental problems. [1] To solve these problems, various types of electrochemical energy storage devices have been developed, such as Li-ion batteries, [2][3][4] Na-ion batteries, [5,6] supercapacitors, [7][8][9][10] and others. [11,12] Among these energy storage systems, Li-ion batteries have attracted attention because of their long cycling life and environmental-friendly properties. As Li-ion batteries were commercialized in 1990, they have been widely applied in various fields, especially electronic devices, resulting in the development of portable electronic devices. [2,13] Recently, electric vehicles (EVs) have attracted attention owing to their zero-pollution property. However, EVs using Li-ion battery systems cannot yet challenge the 300-mile range of the average internal combustion engine. It is very urgent to develop alternative high energy storage devices. The theoretical specific energy of a Li-O 2 battery is 3505 Wh kg À1 when the discharge product is Li 2 O 2 , which is five to eight times higher than that of Li-ion batteries. Even considering the mass of the other battery components, including the positive active material, current collector, and outer packing, the actual special energy of Li-O 2 batteries can reach approximately 500-900 Wh kg À1 . In addition, EVs powered by these batteries have a range of up to 550 km, which is tremendously longer than that achievable with other secondary batteries and the average internal combustion engine. [12] Moreover, their positive active material can be obtained directly from the air, which greatly reduces their cost. As a result, the Li-O 2 battery is regarded as a promising next-generation energy storage system.According to the electrolyte, Li-O 2 batteries are classified as three types, that is, aprotic, hybrid aqueous/aprotic, and all-solid-state Li-O 2 batteries. [14][15][16][17] In this article, nonaqueous Li-O 2 batteries will be discussed. We will elaborate on the structure and mechanism of the nonaqueous Li-O 2 battery. It is composed of a porous positive electrode, nonaqueous Li + electrolyte, and Li metal negative electrode. In the discharge process, oxygen receives electrons and is reduced on the positive electrode, which is also called the oxygen reduction reaction (ORR). The negative metal Li releases electrons to form Li + . Li + moves across the electrolyte, and oxygen combines with the electrons from the external circuit to generate Li 2 O 2 on the cathode surface. Li 2 O 2 decomposes to Li + and O 2 in the charge process, which is the oxygen evolution reaction (OER). [12] Generally, from the respect of reactions on the electrode, electrochemical power sources involve three types, that is, intercalation reaction, conversion reaction, and electrocatalytic reaction (as seen in T...

Review on Recent Advances of Cathode Materials for Potassium‐ion Batteries

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A review of rechargeable batteries for portable electronic devices

“…A breakthrough in increasing the battery energy density requires developing new electrochemical reactions. [83][84][85][86][87][88][89] Along this line, new battery systems have been intensively pursued in recent years, including Li metal batteries, [90][91][92][93][94][95][96] metal-sulfur batteries, 97-104 metal-air (or metal-oxygen) batteries, [105][106][107][108][109] and batteries involving monovalent (eg, Na and K) [110][111][112][113][114][115] or multivalent (eg, Mg, Ca, Zn, and Al) elements/cations. 116 Among various new battery systems, Li-sulfur, Li metal, and Li-oxygen batteries have gained great attraction due to their exceptionally high energy density (Figure 11).…”

“…It has been speculated that existing batteries, including Li‐ion batteries, have limited room for further improvement. A breakthrough in increasing the battery energy density requires developing new electrochemical reactions . Along this line, new battery systems have been intensively pursued in recent years, including Li metal batteries, metal‐sulfur batteries, metal‐air (or metal‐oxygen) batteries, and batteries involving monovalent (eg, Na and K) or multivalent (eg, Mg, Ca, Zn, and Al) elements/cations .…”

Nano‐Sized Au Particle‐Modified Carbon Nanotubes as an Effective and Stable Cathode for Li−CO2 Batteries

“…As reported, almost all organic electrolyte‐based Li‐air batteries use oxygen as the reaction gas, where the CO 2 , H 2 O, etc. in the ambient air will participate in battery reaction to form Li 2 CO 3 , LiOH, etc [7] . These by‐products will deposit on the surface of the cathode and block the porous channels, which further obstructs the deposition and decomposition of the main discharge product Li 2 O 2 [8] .…”