Enhancing the Capacity and Stability by CoFe2O4 Modified g-C3N4 Composite for Lithium-Oxygen Batteries

Abstract

As society progresses, the task of developing new green energy brooks no delay. Li-O2 batteries have high theoretical capacity, but are difficult to put into practical use due to problems such as high overvoltage, low charge-discharge efficiency, poor rate, and cycle performance. The development of high-efficiency catalysts to effectively solve the shortcomings of Li-O2 batteries is of great significance to finding a solution for energy problems. Herein, we design CoFe2O4/g-C3N4 composites, and combine the advantages of the g-C3N4 material with the spinel-type metal oxide material. The flaky structure of g-C3N4 accelerates the transportation of oxygen and lithium ions and inhibits the accumulation of CoFe2O4 particles. The CoFe2O4 materials accelerate the decomposition of Li2O2 and reduce electrode polarization in the charge–discharge reaction. When CoFe2O4/g-C3N4 composites are used as catalysts in Li-O2 batteries, the battery has a better discharge specific capacity of 9550 mA h g−1 (catalyst mass), and the cycle stability of the battery has been improved, which is stable for 85 cycles.

Advances in Carbon Nitride-Based Materials and Their Electrocatalytic Applications

“…A higher specific capacity for discharge of 9550 mAh g –1 was observed when the CoFe 2 O 4 /g-C 3 N 4 composite catalysts were employed in Li–O 2 batteries. Besides, the stability of 85 cycles indicated an improvement in the battery’s cycling stability . A Ag/g-C 3 N 4 nanocomposite modified with Co 3 O 4 was prepared as a cathode catalyst for use in Li–O 2 cells.…”

Nanostructure Engineering of Graphitic Carbon Nitride for Electrochemical Applications

“…176 Their porous structure with large surface area could provide deposition space for lithium oxides and promote mass transfer, and the high electrocatalytic activity would reduce chemical energy barrier accelerating conversion kinetics. 35,177 For instance, Liu et al developed a freestanding macroporous g-C 3 N 4 composite air cathode for high-performance lithium− oxygen batteries, in which g-C 3 N 4 nanosheets provide enough deposition space for Li 2 O 2 and promote charge transfer. 178 g-C 3 N 4 material has been employed in cathodes and electrolytes and achieved good energy capacity and cycling life.…”

“…Moreover, lithium–oxygen batteries are promising candidates as high-density energy storage systems by virtue of the high energy density and sustainability. , Comparing with noble metal nanomaterials, nonmetal g-C 3 N 4 materials are emerging as highly efficient electrocatalysts for oxygen electrodes . Their porous structure with large surface area could provide deposition space for lithium oxides and promote mass transfer, and the high electrocatalytic activity would reduce chemical energy barrier accelerating conversion kinetics. , For instance, Liu et al . developed a freestanding macroporous g-C 3 N 4 composite air cathode for high-performance lithium–oxygen batteries, in which g-C 3 N 4 nanosheets provide enough deposition space for Li 2 O 2 and promote charge transfer .…”

Engineering Metal Alloy Nanocrystals Anchored on N‐Doped Nanoporous Carbon for Li‐O2 Batteries

“…[7][8][9][10][11] The major discharge product Li 2 O 2 , which is intrinsically insulating and insoluble in the electrolyte, is deposited on the cathode surface and further causes the degradation of the LOBs. [12][13][14][15] To data, although some precious metals along with their oxides (Pt, Ru, IrO 2 , RuO 2 ) have shown excellent ORR and OER performance, they cannot be produced in a large scale due to the high cost and low reserve. [16][17][18][19] Therefore, it is imperative to develop the lowcost and non-precious catalysts with high activity and stability for the LOBs.…”

“…Therein, Li + reacts with the oxygen to form the eventual Li 2 O 2 product during the discharging process, which decomposes to the Li + and oxygen in the subsequent charging process [7–11] . The major discharge product Li 2 O 2 , which is intrinsically insulating and insoluble in the electrolyte, is deposited on the cathode surface and further causes the degradation of the LOBs [12–15] . To data, although some precious metals along with their oxides (Pt, Ru, IrO 2 , RuO 2 ) have shown excellent ORR and OER performance, they cannot be produced in a large scale due to the high cost and low reserve [16–19] .…”