The University of Oxford leads on the theme of electrochemical energy storage theme with Henry Royce Institute partners.
The primary focus for research is on next-generation materials for electrochemical energy storage – for use in rechargeable batteries, also known as secondary batteries.
The research facilities for fabrication, testing and characterisation of electrochemical storage materials are available for collaborative research or for technician-supported access. The main equipment capabilities and facilities are summarised in the sections below.
Solid state battery (SSB) cell fabrication starts with a heat box, to dry all precursor materials. Then powders of controlled composition are synthesized from the precursor materials under an inert, controlled atmosphere. Work must be carried out under an inert environment due to high reactivity even at very low atmospheric humidity.
Workflow for solid-state cell fabrication
High-energy ball-milling is widely used for the synthesis of different types of conductors. During high-energy ball-milling, the precursor materials undergo a combined process of mixing, pulverization, amorphization, and solid-state reaction. This allows the synthesis of a variety of materials at room temperature. Ball-milling is also an important tool for the precise grinding and blending of powders before the subsequent processing of electrodes and electrolytes. This applies particularly to solid-state batteries where mixing electrolyte and electrode powder can be used to create ionic pathways at the anode or cathode side.
The facilities enable the fabrication of SSB cells with a controlled architecture of the electrolyte in conjunction with the anode and cathode, which will take a significant step forward with the new addition of an appropriate ball mill capability in a glovebox.
Extensive glovebox handling facilities include load-locks and transfer ports. Key pieces of equipment are installed within the controlled environment, to enable processing of air-sensitive materials.
Sample preparation steps – including weighing, pouch sealing and cell crimping – can be carried out in an inert atmosphere. Argon gas is used to minimise the presence of oxygen and water vapour.
MBraun glovebox suites
Several evaporations and sputter deposition systems are available, for the coating and metallization of small sample areas. A rotating substrate holder helps to ensure even distribution. Deposition systems incorporate plasma cleaning,
programmed shutter opening, and deposition time, with a crystal thickness monitor.
Deposition chambers are housed in gloveboxes with an inert (argon) atmosphere, with low concentrations of oxygen and water vapor. Access to these gloveboxes is made using load locks and sealed sample transfer containers, to help
protect air-sensitive materials.
A list of standard sputter targets and evaporation metals is available on request.
The following Meet the Researcher videos offer an introduction to key techniques and instruments.
https://youtube.com/embed/CiMg4W395jk
MB Provap-5
A 3D printer ^ and nanoscriber ^ are available, for the production of frameworks and fine structures.
The Flashforge Creator Pro ^ is a dual-extrusion 3D printer that uses flush deposition modeling. The build volume is 227 x 148 x 150mm, with positioning precision of 11 microns (X-Y) and 2.5 microns on the Z-axis. Layer resolution is 100~500 microns.
The two Photonic Professional GT laser lithography systems support 3D micro printing and maskless lithography.
The Nextrode project is investigating techniques for fabricating graded electrode structures and is establishing facilities and protocols to support this research at the Begbroke Advanced Processing Laboratory. Techniques include a hot wax inkjet screen printer and film coater in an inert atmosphere glovebox.
Nanoscribe and 3D printer
Tube furnaces and a variety of powder handling, weighing, and milling facilities are available, to support the preparation of electrochemical storage cells.
Press with Digital Programmable Pressure Controller, in Argon glovebox
Built-in load cell with a digital display for pressure measurement and control
Digital control panel for programmable pressure and dwell time
Pressure adjustment range: 0.1-5T Pressure accuracy: +/- 0.003T
Time setting: 1 - 999 minutes
Standard button/coin cell and pouch cell formats can be fabricated.
Coin cells enable rapid discovery and high density cycling tests.
Pouch cells are useful when scaling up and for investigations examining performance across an extended area.
For SSBs and sensitive Li-ion battery materials, testing and disassembly must take place in a glovebox environment.
In operando techniques include XRD and FTIR. Other analysis techniques, such as XPS, NMR, and electron microscopy tools and associated sample preparation techniques are accessed using inert gas transfer cassettes.
Analysis of storage cells
The Horiba LA960A measures the diffraction of laser light to determine the particle size distribution in a sample. It includes an autosampler for high-throughput measurements.
The instrument incorporates two light sources, a sample handling system and a photodiode array, which detects light scattered over a wide range of angles. Requiring only microgram quantities of samples, particle sizes can be determined over the range of 10nm to 5mm, with an accuracy of +0.6%.
Horiba LA960A
Combining a thermogravimetric analyser (TGA) with a mass spectrometer (MS) and autosampler, the Netzsch STA 449 F3 Jupiter allows the measurement of mass changes and thermal effects over a wide temperature range.
Netzsch STA449F3
This high-throughput optical spectroscopy instrument can be operated in a number of modes, including absorbance, luminescence and fluorescence.
Multiple samples can be tested rapidly using the plate reader.
Environmental control holds the samples at target temperatures from 4degC above ambient up to 45degC.
Spectramax i3x
The InVia Qontor incorporates focus tracking capability, enabling analysis of samples with rough, uneven, or curved surfaces.
The spectrometer operates with both 633nm and 785nm excitation directed to an inverted stage. The 785nm source can also be directed into a glovebox using a fibre optic probe, to allow in situ Raman microscopy under an inert/controlled atmosphere.
Renishaw InVia Raman microscope
Gas chromotography with autosampler.
Thermo Scientific Trace 1300
Electrochemical testing.
X-ray diffraction equipment includes hot stage and in operando capabilities, and a Rigaku MiniFlex 600 XRD in a glovebox - which can be used to investigate air-sensitive materials.
Our Rigaku Smartlab systems ^ provide X-ray generation at 3 kW (for sealed X-ray tubes) and 9 kW (for PhotonMax rotating anodes)
The 9kW instrument is also equipped with a sample observation camera, an X-Y translation stage (X, Y +/- 50mm), a micro-focus optics unit (CBO-f), and a HyPix-3000 next-generation 2D semiconductor detector. This detector has a large active area of approximately 3000 mm² with a small pixel size of 100 μm², resulting in high spatial resolution. As a single photon counting X-ray detector offers a high count rate (greater than 10⁶ cps/pixel), a fast readout speed, and very low detector noise.
The Rigaku Miniflex combines electrochemical in situ tools with a controlled atmosphere environment.
The PDXL software suite provides various analysis tools such as automatic phase identification, quantitative analysis, crystallite-size analysis, lattice constants refinement, Rietveld analysis, ab initio structure determination, etc.
Rigaku XRD
The Phi XPS VersaProbe III is a highly automated, high-resolution X-ray photoelectron spectroscopy instrument which uses a scanned, focused, monochromatic X-ray beam specifically designed for spatially-resolved chemical state analysis.
Beam rastering enables the acquisition of secondary electron images and XPS data from the same locations.
The multi-channel detector and fast electronics boost sensitivity and allow rapid data collection. The XPS includes an argon-ion gun.
PhiXPS VersaProbe III
Nano-impedance atomic force microscope in an inert environment.
Bruker Dimension Icon scanning probe microscope
Oxford Instruments’ X-Pulse benchtop NMR spectrometer. Used to characterise the behaviour of a wide range of different elements within novel battery material formulations during electrochemical processes. Development of in-operando NMR operation in an inert glovebox environment.
Oxford Instruments' X-Pulse benchtop NMR
Benchtop NMR in glovebox.
Lab-based X-ray Absorption Spectrometer (XAS) – optimised for Pt, Ir, Ni, Cu, Fe absorption edges (selected based on community consultation regarding elements most relevant for electrocatalysis). This is a new lab-based capability that is being commissioned for future access by the UK community. It offers performance approaching that of synchrotron beamlines. The instrument geometry of the easyXAFS allows both operando cells and ex situ samples to be accommodated. At present, mechanistic studies are often performed at central facilities where access is irregular and highly oversubscribed.
EasyXAFS lab-based XAS system
Impedance analysis testing over a wide frequency range enables the mobility of ions and carriers to be determined in an electrochemical device.
Multichannel cycling capability, for testing button cells in a temperature-controlled environment.
The MSR rotator controller rotates an electrode in an electrochemical cell for rotation rates from 50 to 10,000 rpm.
Electrochemical measurements can be made for rotating disk electrode (RDE), rotating ring-disk electrode (RRDE), and rotating cylinder electrode (RDE) geometries.
Testing elastic modulus at the small scale, the pico-indenter combines scanning electron microscope imaging with electron back-scattering, to identify grain orientation.
The instrument is housed in a glovebox, to maintain an inert atmosphere.
