Critical Insight into the Relentless Progression Toward Graphene and Graphene‐Containing Materials for Lithium‐Ion Battery Anodes

Abstract

that its extraordinary properties would enable revolutionary new technologies, which gave birth to the "graphene era". [ 3,4 ] Relying on this scenario, in 2013, the European Union launched the ¤1 billion "Graphene Flagship" project aimed to investigate the properties of this new form of carbon for various applications (e.g., electronics, sensors and energy storage devices), with the ambitious goal of guiding graphene from laboratories to commercial applications within a decade. [ 5,6 ] In the same period, the Chinese Government set up a similar investment to mass-produce graphene as thin fi lms (e.g., for touchscreen electrodes) and platelets (e.g., for use in batteries). [ 6 ] In the following years, hundreds of patents, mainly focused on manufacturing and application in energy storage, were fi led and the worldwide production of graphene and graphene-containing materials rapidly increased. Although a few Chinese industries claimed to already use graphene-containing materials for smartphone production, no revolutionary practical application relying on graphene has been yet developed. [ 6 ] Specifi cally with respect to the battery fi eld, a close analysis of the scientifi c literature reveals a struggle to meet the ambitious initial targets. A potential loss of focus from the fi nal application caused by hype and ease of publication on such a novel matter, together with the delivery of very misleading information [ 7,8 ] and erroneous statements [ 7 ] concerning the use of graphene in batteries are emerging as possible reasons of the ineffective graphene-era outburst. In this progress report, we do not focus on production and classifi cation of graphene and graphene-containing materials, which were already well reported in the past years. [ 3,[9][10][11] In contrast, due to the lack of an exhaustive analysis of the progression of the use of such materials in lithium-ion battery (LIB) anodes, we report here a critical evaluation of the most prominent research papers published from 2008 until the end of 2015. As shown in Figure 1 , three different stages of the graphene research in LIB anodes can be distinguished: a fi rst stationary phase between 2008 and 2010 where the lithium-ion storage properties of different graphene and graphene-containing materials were preliminarily explored, a second exponential stage, spanning from 2010 to 2014, where graphene and graphene-containing anode materials were broadly developed and investigated, and fi nally, a third phase, (i.e., starting from 2015), where the research seems to have approached a plateau. After Used as a bare active material or component in hybrids, graphene has been the subject of numerous studies in recent years. Indeed, from the fi rst report that appeared in late July 2008, almost 1600 papers were published as of the end 2015 that investigated the properties of graphene as an anode material for lithium-ion batteries. Although an impressive amount of data has been collected, a real advance in the fi eld still seems to be missing. In this framework, atten...

Ultrathin Nitrogen‐Doped Carbon Layer Uniformly Supported on Graphene Frameworks as Ultrahigh‐Capacity Anode for Lithium‐Ion Full Battery

“…[5] To increase the energy and power densities of LIBs, great efforts have been devoted to develop various alternatives to graphite, among which nanostructured carbon materials have received intensive interest due to their high electrical conductivity, low cost, designable structure, and porosity, etc. [5,6] Particularly, 2D ultrathin layer structure can enhance Li-storage ability by bounding Li not only on both sides of nanosheets, but also on the edges, defects, and covalent sites of nanosheets, while the 3D porous network can provide multidimensional electron transport pathway and shorten ion diffusion distance to promote the electrochemical reaction throughout the entire electrode. [7][8][9][10] Meanwhile, the introduction of heteroatom (e.g., N, B, S, F, and P) has been considered as another versatile approach to tune the intrinsic molecular structure of carbon materials, which can create more active sites and increase the electrode/electrolyte affinity and thus improve the Li storage properties to different extent depending on the specific synthetic conditions.…”

“…Graphite, the commercial anode material, cannot meet the increasing demands of rapidly developing LIB markets due to its low theoretical specific capacity (372 mA h g −1 ) and poor rate capability . To increase the energy and power densities of LIBs, great efforts have been devoted to develop various alternatives to graphite, among which nanostructured carbon materials have received intensive interest due to their high electrical conductivity, low cost, designable structure, and porosity, etc . Particularly, 2D ultrathin layer structure can enhance Li‐storage ability by bounding Li not only on both sides of nanosheets, but also on the edges, defects, and covalent sites of nanosheets, while the 3D porous network can provide multidimensional electron transport pathway and shorten ion diffusion distance to promote the electrochemical reaction throughout the entire electrode .…”

A New Strategy for Maximizing the Storage Capacity of Lithium in Carbon Materials

“…Among the electrode materials, the anode can be classified into five categories depending on the reaction mechanism used for storing Li: (a) Li intercalation into graphite, (b) insertion of Li into high-voltage oxides (e.g., TiO 2 ), (c) materials forming alloys with Li (e.g., Si), (d) materials that undergo conversion reactions with Li (e.g., Fe 3 O 4 ), and (e) Li storage in reduced graphene oxide (RGO) ( Figure S1, Supporting Information). [8] Materials belonging to each category present some inherent characteristics not observed in materials of different categories, while also presenting some disadvantages in terms of their practical use. For example, although commercialized graphite is the most common anode material used in LIBs, it cannot satisfy the current demands because of its low theoretical capacity (372 mA h g −1 ) and poor rate performance.…”

“…To satisfy these urgent requirements, there have been intensive efforts to develop new and better electrodes. Among the electrode materials, the anode can be classified into five categories depending on the reaction mechanism used for storing Li: (a) Li intercalation into graphite, (b) insertion of Li into high‐voltage oxides (e.g., TiO 2 ), (c) materials forming alloys with Li (e.g., Si), (d) materials that undergo conversion reactions with Li (e.g., Fe 3 O 4 ), and (e) Li storage in reduced graphene oxide (RGO) (Figure S1, Supporting Information) …”

Three‐Dimensional Graphene‐based N‐doped Carbon Composites as High‐Performance Anode Materials for Sodium‐ion Batteries

“…[1,2] Despite these advantages, the limited lithium resource on earth restricts the applications of LIBs severely.I nview of this, researchers have made great efforts to explore alternative energy storages ystems. [1,2] Despite these advantages, the limited lithium resource on earth restricts the applications of LIBs severely.I nview of this, researchers have made great efforts to explore alternative energy storages ystems.…”