Energy

Energy storage – Silvia Giordani

The implementation of Hydrogen as an alternative energy carrier is impaired by the lack of technologies that can store in a compact and safe way this gas. We aim to provide a new material that can improve current hydrogen storage technologies by exploiting the high surface area of Graphene.

 

The research aims to identify promising pillared graphene-based 3D structures having morphological and chemical features tailored for gas hydrogen sorption. This imply deepening the understanding on the synthesis of these materials in order to correlate chemistry and morphology with function.

We obtained these results:

We designed and synthesized an organic molecule tailored for providing rigid pillaring of graphene oxide (GO). With this molecule we successfully functionalized GO, providing a new material with increased interlayer spacing between the GO sheets. Pillaring of GO was able to increase considerably its specific surface area (SSA).

We also designed and synthesized a library of potential pillaring molecules which differ for their rigidity, size and electronic characteristics. These molecules will be tested to make a set of graphene-based pillared 3D materials.

Current research activities are focused on:

  1. the synthesis of graphene-based 3D materials using pillaring molecules that have different size, shape, rigidity and electronic characteristics;
  2. the determination of SSA and hydrogen sorption capabilities of these new materials (in collaboration with A. Talyzin, Umeå University and Graphene Flagship);
  3. with a continuous feedback mechanism, novel pillars will be designed to maximize the material’s hydrogen sorption capabilities.

Connection with Graphene Flagship project

WP12 – Energy Storage

Researcher – Gas Storage Task

Project leaders - Synthesis of graphene based 3D mesostructures exploiting pillaring with organic molecules.

Conceptual design of 3D layer assembly of two graphene layers by pillaring with an organic rigid spacer.
 Hydrogen gas molecules adsorbing inside two pillared layers of graphene co-linked by an organic spacer.
 

 

Quantum dot solar cells - Iwan Moreels

Quantum dot solar cells offer the possibility of low-cost, solution processed energy generation on a variety of scalable platforms. In these solar cells, graphene can be added both as a novel, flexible electrode or as thin protective film to enhance the stability of the devices.

 

In our work, we fabricate solution-processed PbS quantum dot solar cells. To maintain a solution processed strategy, we work with reduced graphene oxide (rGO), a graphene-based material that can be dispersed in a variety of solvents. Next to rGO, the integration of different transition metal dichalcogenide dispersions is also tested.

Recently, we demonstrated the synthesis of quantum dot – rGO hybrid materials, combining different semiconductors nanocrystals with rGO via short organic linkers. These materials pave the way for integration of PbS-rGO into PbS quantum dot solar cell. Currently, we are fabricating devices and are working on the optimization of the power conversion efficiency.

Connection with Graphene Flagship project

WP11 energy generation - project partner

Picture of different solutions containing colloidal PbS quantum dots
Picture of a PbS quantum dot solar cell

 

Energy conversion - Francesco Bonaccorso

Flexibility, wearability, cost-effectiveness, scalability and sustainability are key-factors for next-generation high-performance energy devices. However, these requirements are hardly met by current state-of-the-art technologies. Graphene and related 2D crystals are promising candidates to face this challenge.

 

We aim at exploiting 2D crystal inks to improve the performances of energy conversion devices. The ‘all-surface’ nature of these materials enables us to on-demand tune their (opto)electronic and (electro)chemical properties via surface chemistry, and the manifold of available 2D crystals give the possibility to create novel hybrid structures.

The ease deposition of our solution-processed inks allowed us to realize, in collaboration with Professor Aldo di Carlo, Tor Vergata University, graphene-based large area solar cells (SCs) modules. Graphene and 2D crystals can be exploited as ideal interface materials both in organic and perovskite solar cells and modules. Moreover, we are demonstrating how graphene and inorganic 2D crystal flakes are excellent catalysts in hybrid organic hydrogen-evolving photocathodes.

Our current research activity is focused on:

  • using graphene-related crystals in photovoltaics as transparent conductive windows, antireflective coatings, photoactive materials, electron/hole transport selective layers, and catalysts;
  • transparent and cost-effective graphene electrodes for large-area façade applications;
  • exploiting 2D materials for high-efficiency organic photocathodes and electrochemical hydrogen evolution;
  • controlling the optical properties of the 2D crystals, to better exploit their band-alignment within hybrid structures;
  • exploring the potentialities of other 2D materials as interface layers in photovoltaic devices.

Example of devices obtained from 2D materials-based inks: 9 cm<sup>2</sup> flexible photo-cathode using graphene oxide as hole selective layer and Pt/C-Nafion overlay (left) and 43cm<sup>2</sup> graphene-based solar cell module (right).

Connection with Graphene Flagship project

WP11 Energy generation: Synthesis and characterization of graphene and other inorganic 2D materials.

Objective: To formulate and provide the required quantities of graphene and other inorganic 2D material inks for the fabrication of printable solar cells and modules.

 


 

Energy storage – Vittorio Pellegrini

We aim at developing new material solutions for next-generation energy-storage devices. In particular, we develop a variety of nanomaterials based on two-dimensional (2D) crystals to be used as conductive additives in anodes and cathodes for Li-ion batteries (LIBs). We also focus on printed 2D-based supercapacitor electrodes. The most technology-oriented work is done in collaboration with industries.

 

Current research activities:

High-capacity and long-cycle life Li-ion batteries combining graphene/silicon anodes with cathodes composed by materials syntesized and nanostructured via bottom-up approaches with 2D material flakes.

Exploitation of different types of layered 2D materials (Mono- and-Di-chalcogenides, MAX phases, black phosphorous, metal oxides, etc.) with carbon-based nanomaterials (i.e., graphene and carbon nanotubes) for the realization of hierarchical (2D and 3D) electrodes for Na-ion and Li-ion batteries.

Technology of printed 2D material-based electrodes for supercapacitors, targeting large–size (300mm×300mm) electrode deposition (in collaboration with Thales SA – TRT).

Development of flexible supercapacitors to be integrated in smart textiles and development of implantable storage devices based on biocompatible/biodegradable materials.

Representative results:

Photograph of the SLG/FLG-SWCNT electrodes printed onto the graphite collector.

The joint effort by IIT and TRT (Paolo Bondavalli) has led to electrodes assembled on a 2 cm2 area with the dynamic spray-gun deposition, achieving gravimetric capacitance, specific energy and power of 104 F g-1, 20.8 Wh kg-1, and 92.3 kW kg-1, respectively (Ansaldo et al., 2017)

 

IIT in collaboration with Trinity College Dublin – TCD (Johnathan Coleman) developed a single-wall carbon nanotube-bridged molybdenum trioxide (MoO3) hybrid anode for Li-ion batteries demonstrating a specific capacity of 865 mAh g−1 at 100 mA g−1 after 100 cycles, with a columbic efficiency approaching 100% and a capacity fading of 0.02% per cycle (Sun et al., submitted, 2017).

Post mortem scanning electron microscope image of the MoO3/SWNT electrode after 50 charge/discharge galvanostatic cycles.

 

We developed a composite made by few-layer graphene flakes produced by liquid phase exfoliation and ultra-small (< 10 nm) silicon nanoparticles synthesized by means of a plasma-assisted aerosol synthesis technique and blended with a poly acrylic acid binder followed by annealing in H2 atmosphere. The as-produced anode (tested in half-cell configuration) displayed a specific capacity of 1500 mA h gSi-1 at maximum, stable over 300 cycles with a Coulombic efficiency exceeding 99% and 99.8% at the 20th and 300th cycle, respectively (Greco et al., 2017).

 


Liberato Manna’s group

under construction