A research team led by Guihua Yu research group at University of Texas at Austin, USA collaborated with Ping Wu research group from Nanjing Normal University, China, developed a double-network hydrogel-reduction route for chemically binding scaffolded anodes with 3D graphene architectures. The paper entitled “Chemically Binding Scaffolded Anodes with 3D Graphene Architectures Realizing Fast and Stable Lithium Storage” was recently published in Research (Research 2019 Article ID: 8393085 DOI: 10.34133/2019/8393085). https://spj.sciencemag.org/research/2019/8393085/.
Graphene, a sheet of carbon atoms bound in a honeycomb lattice pattern, is electrically conductive, chemically inert, eco-friendly and sustainable, and flexible with large surface area for numerous applications. Building three-dimensional (3D) graphene materials from 2D units can effectively prevent the self-stacking and maintain the unique physicochemical properties toward electrochemical energy-storage and conversion. For lithium storage, 3D graphene-based electrodes can be light, durable and suitable for high capacity energy storage and faster charging times.
To meet the ever-growing requirements in Li-ion batteries (LIBs), searching for alternative anodes to commercial graphite with limited capacity has become an urgent task. Metal alloys, oxides, sulfides and other high-capacity anodes have been applied to incorporate into 3D graphene for improved energy storage performances. However, current anodic guests often exist in the form of nanoparticles, physically attached to graphene hosts, and therefore tend to detach from graphene matrices and aggregate into large congeries, causing considerable capacity fading upon repeated cycling.
To overcome this issue, Guihua Yu research group at University of Texas at Austin, USA, collaborated with Ping Wu research group from Nanjing Normal University, China, developed a double-network hydrogel-reduction route for chemically binding scaffolded anodes with 3D graphene architectures. “Compared with 0D nanomaterials, scaffolded anodes manifest collective advantages of both nano-building units and micro-sized assemblies, and moreover, chemically bonded hybrid anodes show enhanced lithium-storage kinetics than the ones hybridized only on the physical level. Chemically binding anodic scaffolds with 3D graphene has great potential in developing advanced electrode materials for LIBs,” comment the scientists from Yu Group.
The study ‘Chemically Binding Scaffolded Anodes with 3D Graphene Architectures Realizing Robust and Fast Lithium Storage’ was published on Aug. 19th in Research, the first Science Partner Journal recently launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST). Dr. Guihua Yu is a professor of Materials Science and Mechanical Engineering at UT Austin.
A scalable hydrogel-reduction route was developed for chemically binding anodic scaffolds with 3D graphene architectures, using double-network hydrogels, containing a unique cyano-linked polymer hydrogels (cyanogels) and graphene oxide (GO) hydrogels, as precursors. Taking tin-based alloy anodes with good application prospect as an example, the simultaneous gelation reactions for Sn–Ni cyanogel and GO gel result in the formation of integrative double-network gels at the same time. This is the prerequisite of subsequent incorporation of Sn−Ni alloy scaffold into 3D graphene architecture effectively and uniformly(Fig. 1).
Fig. 1 Lithiation/delithiation process in Sn–Ni/graphene dual frameworks and their cycling stability, (b) rate capability vs. only Sn–Ni scaffold: (a) cycling stability, (b) rate capability
When applied as anodes in LIBs, the Sn–Ni/graphene dual frameworks realize long-term cyclic stability and high rate performance toward lithium storage. ‘The dual framework consists of physical-intertwined and chemical-bonded Sn−Ni alloy scaffold and graphene architecture. This is the key point of Sn−Ni/G hybrid anode to achieve remarkable structural stability and charge-transport capability. To span our knowledge regarding the mass/charge transport process during Li-ion storage, we still have a long way to go’.
Tag: Emerging materials research