Graphene-based quasi-solid-state lithium–oxygen batteries with high energy efficiency and a long cycling lifetime

Abstract

An aprotic lithium-oxygen battery with an ultrahigh theoretical energy density has attracted significant attention as the next-generation electrochemical energy device demanded by all-electric vehicles and other high-energy devices. Extensive effort has recently been devoted to improving the performances of cathodes, anodes, and electrolytes. However, as an integrated system, the overall battery properties are not determined by the individual components but by the synergy of all components. Despite important progress in the development of cathodes, anodes, and electrolytes, the system-level design and assembly of lithium-oxygen batteries have not benefited from these recent advances. Here, we report a graphene-based quasi-solid-state lithium-oxygen battery consisting of a rationally designed 3D porous graphene cathode, redox mediator-modified gel polymer electrolyte, and porous graphene/Li anode. This integrated prototype battery simultaneously addresses the major challenges of lithium-oxygen batteries and achieves stable cycling at a large capacity, low charge overpotential and high rate in both coin-type and largescale pouch-type batteries. For the first time, these lithium-oxygen batteries as a whole device deliver gravimetric and volumetric energy densities higher than those of a commercial Li-ion polymer battery. This study represents important progress toward the practical implementation of full-performance lithium-oxygen batteries.

Graphene‐Based Nanomaterials for Flexible and Stretchable Batteries

“…[105][106][107][108][109] Pore generation is often used in the electrochemical research fields in order to increase the surface area of the electrodes. [110][111][112][113][114] Porous structures of CVDgraphene films were fabricated with porous Ni foils, originated from de-alloyed Ni-Mn foils. [68] These kinds of structural transformations of planar graphene to form a large surface area without deteriorating the flexibility have been evaluated as suitable for fabricating high-performance flexible battery electrodes.…”

“…CVD process with de-alloyed NiMn foils N-doped graphene Flexible in batteries [114] Graphene foams (for LIBs) CVD process with Ni foams Graphene foam Flexible in batteries (radius of 5 mm) [71] Graphene foams with sulfur loading (for LSBs) CVD process with…”

Electrode Protection in High-Efficiency Li–O2 Batteries

“… 23 For example, Chen et al reported a porous graphene/Li anode by infusing molten Li into a free-standing, bicontinuous porous N-doped graphene scaffold ( Figure 3 b). 13 This composite anode can simultaneously resolve the dendrite growth and pulverization of Li metal anode, as a result, significantly boosting the cycling stability of Li–O 2 batteries. However, it should be noted that the introduction of the 3D host will undoubtedly decrease the energy density of the Li–O 2 batteries, whereas the high surface area increases the possibility of Li metal involved side reactions.…”

“…As a routine quasi-solid-state electrolyte, gel polymer electrolyte (GPE) with low cost and moderate Li + conductivity has been demonstrated effective in reducing side reactions, suppressing dendrite growth, and inhibiting RMs induced shuttle attack in the Li metal anode, enabling its stable operation in Li–O 2 batteries. 13 Although these positive effects, the GPE with a limited amount of liquid electrolyte still suffers from the issues of low Young’s modulus, volatilization, and less efficient O 2 blockage. As a result, solid-state electrolyte (SSE) stands out owing to its unique advantages of relative high Young’s modulus, nonvolatility, as well as the only Li + transportation ability that fully isolates the crossover of undesirable components.…”

“…Presently, carbon-based materials, like graphene and carbon nanotubes (CNTs), are the most widely used O 2 cathodes for Li–O 2 batteries. 13 − 17 However, the vulnerability of carbon materials toward the aggressively oxidative species can induce severe cathode passivation and a fast increase in charge voltage, 7 , 18 − 21 consequently, lowering the round-trip efficiency and sustainable cycling of Li–O 2 batteries. For the anode part, the ultrahigh capacity (3860 mAh/g) and the lowest redox potential (3.04 V vs SHE) of metal Li make it indispensable and the only choice for the Li–O 2 battery to achieve the theoretical specific capacity.…”