Hithium launches sodium-ion cell for 20,000

Hithium has launched a new sodium-ion battery cell and a 4MWh battery energy storage system (BESS), promising a 30-year expected operational lifetime. The Chinese manufacturer introduced the ∞Cell N785Ah cell and the ∞Power N4.0MWh BESS in a pre-recorded video streamed live on LinkedIn yesterday.

Dr Aileen Wang, Hithium's research institute director, said the company's sodium-ion team was tasked years ago with building a battery to redefine energy storage. They saw potential in sodium-ion as lithium-ion cost curves began to flatten. "We did not just follow lithium-ion," Wang stated. "We wanted to explore where lithium-ion has yet to go, to see whether electrochemical energy storage could operate over a much longer timeframe."

Cell and system specifications

The ∞Cell N785Ah is designed for a 20,000-cycle service life and supports storage durations from two to eight hours. Hithium claims it is fully compatible with the company's existing 1,000Ah lithium-ion manufacturing platform, which would allow for rapid scaled mass production.

The ∞Power N4.0MWh BESS uses an original sodium-ion architecture. It features a stacked cell design with a dedicated battery management system (BMS). Hithium claims this BMS can estimate the state of charge to within 2.5% accuracy. The system is compatible with 800V to 1500V power conversion systems.

Overcoming material challenges

Wang outlined several material challenges the team had to overcome. Cathode impurity phases were hard to control. Combining high specific capacity with fast anode kinetics proved difficult. Interfacial side reactions and film formation mechanisms in the electrolyte were not fully understood.

Hithium worked with partners to develop a high phase-purity sodium iron phosphate pyrophosphate (NFPP) cathode material. This increased conductivity by three orders of magnitude and raised phase purity to 97%. The development helped reduce battery costs and increase energy density.

For the anode, the company developed a hard carbon material with fast sodium-ion transport channels. Wang claimed this combines ultra-low expansion with high-rate performance. It also substantially extends calendar life.

Manufacturing advancements

The company developed a sodium-ion-specific electrolyte formulation. It uses micro-bonding and targeted repair mechanisms. Ion diffusion was improved. The desolvation barrier was lowered by using low-viscosity, weakly coordinated solvents.

A dense solid electrolyte interphase (SEI) layer on the anode surface suppresses electrolyte decomposition. This significantly reduces gas generation and improves lifecycle reliability.

Wang explained three core manufacturing capabilities. An ultra-thick electrode coating offsets sodium-ion's energy density disadvantages. Long-life structural components handle expansion and contraction for over 20,000 cycles. Large-format cell stacking technology overcomes manufacturing bottlenecks.

Hithium aims to use many of the same processes as its lithium-ion lines. The shift would use abundant materials uncoupled from global lithium battery supply chains.

Sodium-ion's commercial progress

Hithium's launch is a sign of progress in commercializing sodium-ion batteries for stationary storage. The push is driven largely by China's major lithium-ion battery manufacturers.

The company claims it was first to market with a sodium-ion cell designed specifically for utility-scale BESS. It launched the ∞Cell N162Ah NFPP battery in December 2024.

Other players have followed with sodium-ion product launches. They include Chinese firms CATL, BYD, HiNa, and Envision. Non-Chinese startups like Peak Energy in the US and Phenogy in Europe are also active. CATL signed a 60GWh sodium-ion battery supply deal with Chinese system integrator HyperStrong in April. It held a global launch for the sodium-ion version of its TENER BESS unit at Intersolar Europe in Germany in June.