Carbon‐Free Cathode Materials for Li−O₂ Batteries

Abstract

Rechargeable lithium‐oxygen batteries, especially the nonaqueous lithium‐oxygen batteries have attracted much attention in recent years due to their high energy densities. However, few critical challenges remain to be overcome, including the low round‐trip efficiency, high charge overpotential, poor cycling performance, decomposition of electrolyte, and instability of the carbon‐based electrode. Among these, the instability of the carbon‐based electrode is one of the major problems that hindered the practical application of the Li−O2 batteries. Much work has been done to solve this problem and there are two widely‐applied strategies: modification of carbon and designing a “carbon‐free” cathode. In this review, we will introduce recent achievements of both strategies.

Thermal safety and thermal management of batteries

“…Therefore, there is an urgent need to design and develop an electrolyte for various extreme environments, such as high-temperature-resistant solid electrolytes, 127 gel polymer electrolytes, 119,128 and molten salt electrolytes. 120,129 In terms of cathode design, developing new types of electrodes such as carbon-free electrodes 120,130 is also a feasible option to avoid parasitic reactions brought about by the intensely oxidizing superoxide. For the anode, the alternatives to lithium metal that have the properties of acting as an adequate source of lithium and high safety, such as silicon anodes, are perhaps more practical in the form of the lithium-ion air battery.…”

Research Progress and Future Perspectives on Rechargeable Na‐O2 and Na‐CO2 Batteries

“…[20] Li-O 2 batteries could deliver extraordinarily large theoretical specific energy of 3502 Wh kg −1 (based on 2Li + + O 2 + 2e −-↔ Li 2 O 2 ), which is an order of magnitude higher than for the commercial LIBs based on the continuous insertion/extraction of Li ions between graphite and LiCoO 2 (387 Wh kg −1 ). [21][22][23][24] Despite its great potential, several daunting issues, including sluggish oxygen redox kinetics, and notorious reversibility and cyclability problems, overshadow any practical applications of Li-O 2 batteries with satisfactory performance. [25][26][27][28] Their large overpotential would eventually result in low round-trip efficiency and poor cycling stability.…”

A dual-electrolyte system for highly efficient Al–air batteries

“…Al–air, Mg–air, Zn–air, Li–air, and Na–air) possess many merits, such as high safety, environmental protection, and high energy density, exhibiting bright development and application prospects. 3–7 Among them, Al–air batteries demonstrate great potential due to their high specific capacity (2980 mA h g −1 ), the abundance of resources, and the low cost of Al. 8,9…”