Benchmark Mineral Intelligence's second mid-month price assessment said the former was up 114.3% and battery-grade material was up 103.4% since the start of 2021.

Technical grade lithium carbonate had risen 4.5% in the past two weeks to US$12,700 per tonne and battery-grade by 6% to $13,625/t, the battery supply chain research and price reporting agency said last week.

It said the prices were rising at a more stable rate as low availability hampered transaction volumes.

Activity in the sector is picking up and ASX-listed producers Orocobre and Galaxy Resources today announced an A$4 billion merger to create the fifth largest global lithium chemicals company.

Macquarie last week tipped the overall lithium market to be in deficit from next year, saying the bullish outlook for EV sales required a substantial upgrade in the outlook for lithium.

Industry sources were predicting prices above RMB100,000/t ($15,300/t) in 2021, Benchmark said.

It also said the lithium hydroxide price was continuing to pick up the pace and narrow the gap to carbonate, rising 11.5% in the past fortnight, or 44.3% so far this year, to $11,475/t.

Cathode producers within China had begun to escalate hydroxide orders as a cheaper feedstock, it said.

"Benchmark expects the gap between carbonate and hydroxide to close, yet increased demand for hydroxide will also prop up carbonate demand growth as an intermediate, stalling a return to a typical hydroxide premium," it said.