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Doug Bright
Critical Resources has added weight to its battery technology program after reporting its sulphur-free electrolyte has delivered room-temperature performance comparable to that of leading sulphide-class materials.
The company says its first-pass amorphous solid-state electrolyte has returned ionic conductivity of 3.2 milliSiemens per centimetre and activation energy of 0.27 electron volts in testing at the South Dakota School of Mines and Technology in the US.
Those numbers are two of the key measures used to judge electrolyte performance, with the result indicating lithium ions can move quickly through the material without the temperature sensitivity that has traditionally hampered many rival chemistries.
Importantly, the company says the values measured at South Dakota were benchmarked against published, peer-reviewed scientific literature, providing an externally referenced basis for comparisons of its present and future performance.
โThis is early-stage laboratory validation, but the technical merits are very encouraging.โ
Critical Resources managing director Tim Wither
For Critical, the bigger prize is manufacturability. Sulphide electrolytes are widely regarded as top performers, but they can release toxic gas on contact with moisture and usually need inert-atmosphere processing, which has long been seen as one of the main barriers to commercial scale-up.
The company says achieving equal transport performance without sulphur could point to a safer and potentially lower-cost manufacturing route.
The result also gives more weight to Critical Resourcesโ broader battery push. In late April, the company said it had secured an evaluation licence over thermal management technology from Singaporeโs Nanyang Technological University before converting it to a full worldwide commercial licence last week.
That technology is aimed at cooling lithium-ion batteries and high-density electronics in warmer operating environments by spraying a non-conductive fluid directly onto hot components, giving the company a parallel stream of work around battery heat management.
Critical Resources managing director Tim Wither said: โBenchmarking our first-pass ASE results against published peer-reviewed literature reveals a performance position that is a result of years of combined research by Dr Smirnova and the SDM team. Being competitive on ionic conductivity โ and matching sulphide-class activation energy – from an initial composition is a strong starting point.โ
Critical says its electrolyte work also complements its dry supersonic deposition manufacturing program, with both streams designed to lower materials and manufacturing risk as the company works towards more representative solid-state cells.
The company says its new amorphous solid-state electrolyte delivers ionic conductivity competitive with non-sulphide, non-halide amorphous electrolytes and an activation energy comparable to sulphide electrolytes, but without the challenges associated with sulphide-based chemistry.
Both test results are from a non-optimised battery electrolyte composition, with further potential improvements likely through ongoing work. Accordingly, the companyโs next steps will include improving the electrolyte composition and carrying out interfacial testing to analyse how effectively lithium ions move across the solid-to-solid boundaries.
Compression studies will test how well the battery materials stay connected during operation, an important step before the company moves to more advanced battery cells. The work will also focus on making sure the electrolyte works properly with the batteryโs cathode before full-cell testing begins.
The company recognises that development is in its early days and it is not yet claiming commercial readiness. However, its latest benchmarked win certainly seems to have given Critical a strong talking point in a crowded battery race.
If the laboratory work keeps delivering, the market may start paying closer attention to what is quietly becoming a broader battery play.
Is your ASX-listed company doing something interesting? Contact: mattbirney@bullsnbears.com.au
