Extra Li-Ion Storage and Rapid Li-Ion Transfer of a Graphene Quantum Dot Tiling Hollow Porous SiO₂ Anode

Abstract

Graphene is widely used to enhance the electrochemical performance of anodes. However, graphene tends to be vertical with the lithium-ion (Li+) diffusion direction, and a few heterointerfaces are formed between graphene and active materials by point-to-point contact. Herein, a graphene quantum dots (GDs) tiling hollow porous SiO2 (HSiO2@GDs) anode is predicted by density functional theory (DFT) and is achieved by experiments. Due to the ultrasmall size, the tiling of GDs would provide Li+ a rapid diffusion channel and abundant heterointerfaces (face-to-face contact) between the GDs and the hollow porous SiO2 (HSiO2). Moreover, owing to the higher electrostatic potential of SiO2, the large-scale local electrical field from GDs to HSiO2 is established at the heterointerfaces, which provide extra Li+ storage sites and further facilitate the Li+ transfer. To our knowledge, the HSiO2@GDs shows the highest specific capacities at various current densities (such as ∼1100 mA h/g at 5 A/g and ∼2250 mA h/g at 0.2 A/g) among reported silicon oxides anodes and presents excellent cycling stability (∼1000 mA h/g after 2000 cycles at 3 A/g). Moreover, the design idea is available to design other widely studied graphene-containing anodes such as the Si, SnO2, TiO2, and MoS2.

Surface functional group‐tailored B and N co‐doped carbon quantum dot anode for lithium‐ion batteries

“…[10][11][12][13] Recently, CQDs have also been employed as surface engineering agents for energy storage and conversion fields on their applicability to various electrode materials and advantageous functions that can support the electrical conductivity, specific capacity, and ion diffusion kinetics of conventional electrode materials. [14][15][16][17] The various advantages of CQDs including high surface area, low toxicity, low cost, and chemical stability, facilitate their use as electrode material modification agents. However, CQDs intrinsically possess many trivial oxygen-containing groups (C O and C OH) at the surface, which can inhibit Li + accessibility to charge storage sites and induce inferior kinetic properties.…”

“…Originally, similar to other quantum dot‐based materials, CQDs have been actively used in the sensing, photocatalysis, and biochemistry fields owing to their simple synthesis, non‐toxic nature, and broad optical absorption 10‐13 . Recently, CQDs have also been employed as surface engineering agents for energy storage and conversion fields on their applicability to various electrode materials and advantageous functions that can support the electrical conductivity, specific capacity, and ion diffusion kinetics of conventional electrode materials 14‐17 . The various advantages of CQDs including high surface area, low toxicity, low cost, and chemical stability, facilitate their use as electrode material modification agents.…”

Biomass‐Derived Hierarchically Porous (Nitrogen, Phosphorus) Co‐Doped SiOx/C Composite Nanosheet Architectures for Superior Lithium Storage and Ultra‐Long Cycle Performance

“…SiO x nanostructures including nanoparticles, nanospheres, nanowires, nanotubes and even various porous two-dimensional structures have been found capable of minimizing the mechanical strains of reactions caused by the volume changes. [22,23] Well-designed protective layers such as carbon-coated, conductive polymersencapsulated, core-shell and yolk-shell structures enable to not only protect the surfaces but also tolerate the volume variations. [9,15,24] Particularly, novel SiO x /C composites with internal voids for volume expansions, stable shells for prevention of electrolyte infiltration and erosion, and high conductive carbon-based materials for improvement of electrical conductivity have been well demonstrated using nanostructuring technologies and/or carbon surface-coating strategies.…”

“…Therefore, nanostructuring and construction of protective layers are expected to be capable of improving rate capability of and prolonging cycle lifetime of SiO x anodes in terms of shortening of Li + transport and reaction pathways, stress relaxation and surface protection. SiO x nanostructures including nanoparticles, nanospheres, nanowires, nanotubes and even various porous two‐dimensional structures have been found capable of minimizing the mechanical strains of reactions caused by the volume changes [22,23] . Well‐designed protective layers such as carbon‐coated, conductive polymers‐encapsulated, core‐shell and yolk‐shell structures enable to not only protect the surfaces but also tolerate the volume variations [9,15,24] .…”

Boron Nitride- and Graphene-Supported Trimetallic Yolk–Shell and Hollow Nanoparticles

“…In the last decade, yolk–shell nanoparticles (YSNPs) have received great attention due to their unique structures that make them suitable for many applications, including nanocatalysis, − sensors, , batteries, − and medicine. , In addition, recently, hollow nanoparticles (HNPs) have attracted wide attention. HNPs with superior properties exhibit great potential in catalysis, − batteries, − drug delivery, − and solar cells …”