The first lithium-ion batteries made with graphite from the namesake project of Sarytogan Graphite Ltd (ASX:SGA) in Kazakhstan have displayed “exceptional endurance” in long-cycle performance.
Coin-cell batteries manufactured by the company’s American technology partner from Sarytogan Uncoated Spherical Purified Graphite (USPG) have now charged and discharged more than 140 times. After the benchmark 100 charges, they retained 97.3% capacity.
Extrapolating the performance to date suggests that up to 1,000 charges are possible until the typical useful threshold of 80% capacity.
“This performance is further remarkable, as coated graphite is usually required to attain this performance,” said Sarytogan.
The performance of these batteries after nine cycles was previously reported as superior to many synthetic graphite products used as the anode in lithium-ion batteries for electric vehicles.
Sarytogan managing director Sean Gregory said, “We are delighted with the endurance demonstrated by Sarytogan Graphite in lithium-ion batteries. This high performance is only possible with highly crystalline graphite, validating Sarytogan Graphite’s premium micro-crystalline nature.
“These results are all significant inputs into the pre-feasibility study which is progressing well and is on track for completion in Q3 this year.”
Premium micro-crystalline graphite
This result provides further validation that Sarytogan Graphite can be best described as 'premium micro-crystalline graphite', and that classifications such as amorphous, flake and vein and even natural vs synthetic are over simplistic.
Sarytogan Graphite is again demonstrating many of the best characteristics of each graphite type.
This high performance in electrochemical applications is only possible with highly crystalline graphite. Individual graphene layers are a very strong hexagonal lattice molecule of carbon atoms. These layers are held together by weaker Van-der Waals forces.
High degrees of this crystallinity facilitate the intercalation of lithium-ions between graphite layers in batteries.
Highly crystalline graphite anodes facilitate Intercalation of Lithium Ions for battery performance.
Further improving performance
Lithium-ion batteries have also been made from Coated Spherical Purified Graphite (CSPG), with the Sarytogan USPG coated to make CSPG. This is the value-adding step of surface coating the USPG with carbon to reduce surface roughness further improve battery performance, particularly in the first cycle.
Another batch of lithium-ion coin cell batteries has now been manufactured using Sarytogan CSPG. Cycle testing has recently commenced and initial results will be reported shortly.
These tests are all important inputs into a pre-feasibility study, which is on track to be completed during the third quarter (July-September) this year.
Read more on Proactive Investors AU
