Cell teardown and characterization of a Hina commercial sodium-ion battery

Summary Transparent insight into the design and materials of commercial sodium-ion batteries is essential for assessing their maturity and benchmarking against lithium-ion technologies. We report postmortem analysis and electrochemical testing of the most commercialized sodium-ion battery technology from Hina Battery, which employs a tabless double-aluminum architecture and a novel cathode composition, NaCu1/9Ni2/9Fe1/3Mn1/3O₂. This cathode features a distinctive spatial separation of copper from the other transition metals (Ni, Fe, and Mn) within individual particles. Using an Archimedean-spiral analysis of computed tomography data, we estimate total cathode length with 2% deviation, without additional image optimization. The cell delivers performance and production quality comparable to state-of-the-art Li-ion batteries: impedance variation across 120 cells is 5.3%, capacity remains over 100% at 4C (25°C), and usable discharge energy above 80% at −20°C, though this value drops to 56% in the charging direction.