Battery Materials

Continuous precipitation of battery pCAM

COBC Technology Overview

COBC/R systems combine baffled and jacketed serpentine pipework with an oscillator system to provide uniform mixing, leading to very efficient heat and mass transfer. The net flow rate is independent of the high fluid velocity and excellent mixing created by the oscillation, allowing extended residence times under plug flow conditions.

Battery materials with NiTech continuous oscillatory baffled crystalliser (COBC)

 

The combination of orifice baffles and oscillated process fluid flow creates eddies between the baffles, providing a uniquely efficient mixing environment that enhances heat and mass transfer rates. The efficient heat and mass transfer speed up the process and ensure a consistent processing environment, while the jacketed pipework provides a large surface area for heat transfer to the process medium. For a typical cooling crystallization process, temperature zones are setup along the length of the COBC, starting from high temperature (at the start of the COBC) through to low temperature (at the end of the COBC). The modular nature of the serpentine pipework means there is a high degree of flexibility in configuring temperature zones for both crystallizations and reactions.

This is the essence of the NiTech Solutions COBC/R system: optimal heat transfer combined with uniform mixing, ensuring you can make right product first time, every time, allowing kinetic (theoretical) reaction times obtained in labs to be delivered at pilot and full scale.

Application overview

To date, batch processing has been the preferred method of synthesising precursor cathode active material (pCAM). Many established industries are burdened with legacy batch process equipment as a result. Batch processing of pCAM, co-precipitation in stirred tank reactors, is very time consuming (30+ hours in some procedures), which limits process throughput. Batch manufacturing has drawbacks, including inconsistency in product quality and performance between batches – both are highly undesirable in battery manufacture.

Continuous co-precipitation using NiTech COBC technology tackles many of the issues associated with batch processing by offering a platform that is significantly smaller in footprint and reactor volume, as well as providing uniform processing conditions. The enhanced heat and mass transfer characteristics can facilitate reduced processing times and lower energy usage, ultimately supporting cost reductions in pCAM manufacture.

Equipment for continuous precipitation of battery pCAM

NiTech Solutions can design processing solutions across a range of scales for the continuous precipitation of battery pCAM.

Battery materials manufacture with NiTech Solutions DN15 Lite

The DN15 range offers a range of opportunities for small-scale process development work on safer compounds and chemistries.

NiTech Solutions DN15 MAX Series for Battery Materials

For more hazardous compounds and processes, the DN15 MAX Series provides a DN15 crystallizer with the required ancillary equipment (pumps, valves, heaters, etc.) and a single interface control system capable of remote operation.

Results from small-scale equipment can be used to design bespoke units for pilot- or production-scale with the ability to produce in the tonne/day range.

Example processes

NiTech Solutions has proven the feasibility of continuously co-precipitating NMC 811 pCAM in a COBC and were able to produce product with comparable crystallographic structure and electrochemical performance. This work was conducted through a collaborative project with CPI and the University of Sheffield utilising Innovate UK funding as part of the Faraday Battery Challenge.

 

 

The project showed successful production of NMC811 pCAM in a continuous flow reactor. During optimisation work, it was proven that product quality can be directly influenced by changing chemical (e.g. reactant concentrations and ratios) and mechanical variables (e.g. mixing intensity), with larger improvements seen when changing physical inputs.

 

 

All samples produced yielded the desired crystallographic structure, confirmed by x-ray diffraction, with low levels of nickel-lithium cation mixing, 0.8%-2.8%, after calcination. These results are comparable with commercially available material produced using a conventional batch manufacturing setup.

Electrochemical capacities of the continuously produced materials were yielded by testing in half coin cells. Maximum capacities of around 200mAh g-1 were achieved, with good capacity retention after 25 cycles, see figure 2.

Long-term cycling of the best sample from the project showed very similar specific discharge capacity and capacity retention over 125 cycles compared with commercially available material, see figure 3.

During the project there was a significant improvement in the bulk density of the pCAM, increasing from 0.6g cm-3 to 1.0g cm-3, see figure 4.

 

 

 

Although these results are promising there is still further development work required to further increase product tap density and scale the process up.

Continuous manufacturing has enabled a significant reduction in processing time and allows for added methods of reaction control. By accelerating the development of new manufacturing processes, NiTech is helping the industry meet consumer demands for safety, reliability, and affordability and is reducing emissions across the entire supply chain.

It’s an example of how a unique collaboration between academia, industry and innovation centres can help solve the challenges that face our society. Together, we’re driving real change to strengthen the UK’s position as a world leader in high-value battery production.

Features and Benefits of COBC for battery materials manufacture

Feature

Low crystallizer volume

Small system footprint

Optimal yields (~95% of theoretical yield)

Consistent product quality (particle size and purity)

Modular crystallizer design

Simple linear scale-up to larger throughputs

C1D1/ATEX-certified units available

Benefit

Smaller and safer manufacturing facilities

Distributed or on-demand manufacturing

Maximising manufacturing efficiency

No batch-to-batch variability

Flexible configuration of production systems

Lower development costs

Rated for use in hazardous environments