Current Landscape of Sodium-Ion Battery Development: CBAK Energy’s Progress in Large Cylindrical Sodium-Ion Cells

Recently, the “10th International Forum on Cathode and Anode Material Technologies for Advanced Batteries & The 4th Forum on Sodium Battery Technology and Market Development” successfully concluded in Suzhou. Co-hosted by the China Industrial Association of Power Sources (CIAPS) and Advanced Battery Materials/Beijing Yihui Information Technology Co., Ltd., the event featured 18 thematic sessions and 74 keynote presentations, attracting 40 exhibitors, 300 participating companies, and over 800 attendees.

During Session 12 (“Development and Progress of Sodium-Ion Batteries and Key Materials”) of the 2026 SIB-4 forum, Dr. Wang Senlin, Head of Sodium-Ion Battery R&D at CBAK Energy, delivered a keynote speech titled “Development Progress of Large Cylindrical Sodium-Ion Batteries.”

Dr. Wang Senlin, Head of Sodium-Ion Battery R&D at CBAK Energy.

Dr. Wang began by introducing the developmental background of sodium-ion technology. He explained that the underpotential deposition of hard carbon ensures the excellent fast-charging kinetic performance of sodium-ion batteries. In terms of safety, the thermal stability of sodium-ion batteries is comparable to lithium iron phosphate (LFP) batteries and superior to ternary (NMC) batteries, which is likely due to the higher internal resistance of hard carbon. According to first principles, the performance advantages of sodium-ion batteries already have theoretical backing; the remaining challenge is how to fully unlock this potential.

The Sodium-Ion Market is Poised for Explosive Growth

Regarding market opportunities, CBAK Energy has consistently focused on the 32, 26, and 40 series cylindrical battery products. The company believes the core applications for sodium-ion batteries cover light motive power, start-stop systems, AIDC (AI Data Centers), UPS, residential energy storage, portable energy storage, commercial and industrial (C&I) energy storage, grid-side energy storage, and electric vehicles.

Institutional research data shows that in 2024, the energy storage sector accounted for 60% of the sodium-ion battery market segment, primarily utilizing 71-series large prismatic cells. From January to September 2025, energy storage continued to dominate the sodium-ion application market, while light motive power also experienced steady growth. Consequently, CBAK Energy’s strategic focus is primarily set on light motive power, electric vehicles, and start-stop applications.

Simultaneously, national policies are guiding the industry’s development. In September 2025, the National Energy Administration of China issued the Guiding Opinions on Promoting High-Quality Development of Equipment, which explicitly highlighted sodium-ion batteries. Furthermore, a “lithium-sodium complementary” strategy was proposed in December 2025, which is expected to facilitate the global transition to a new energy economy.

CBAK Energy initiated its strategic layout in sodium-ion technology as early as 2021. By 2023, it took the lead in achieving mass production of the 32140 large cylindrical sodium-ion battery and completed all necessary product certifications. Leveraging the robust advantages of its cylindrical cell ecosystem, CBAK Energy can currently customize large cylindrical full-tab sodium-ion batteries across the 32, 26, 40, and 60 series.

Overcoming Technical Bottlenecks in Sodium-Ion Technology

“Why do we consistently focus our efforts on cylindrical batteries?” Addressing this question, Dr. Wang explained that the large cylindrical full-tab structure provides a strong overcurrent capability, which fully unleashes the high-rate charge and discharge characteristics inherent to sodium-ion batteries. However, the technology development process also faces numerous pain points and challenges.

01 Pain Points and Solutions for Layered Oxide Sodium-Ion Batteries

The main issues facing the layered oxide system are the poor air stability of the cathode material, high-voltage failure, and elevated temperature rise during high-rate charging and discharging. Although these batteries can achieve 15C/20C discharge rates, their temperature increase remains relatively high.

Drawing on research related to the failure modes of ternary layered oxide cathode materials in lithium-ion batteries, the primary failure modes are active material loss and conductive network failure. To address these issues, the company has implemented targeted optimizations at the material, electrode, and cell structure levels. For the electrodes, different types and amounts of conductive agents are compounded to form a three-dimensional conductive network, achieving low impedance and extended battery life. Structurally, a full-tab design is employed to ensure superior overcurrent capability.

02 Pain Points and Solutions for Polyanion Sodium-Ion Batteries

For polyanion sodium-ion batteries, the primary pain points are fast-charging performance and low-temperature charge/discharge cycling. Currently, low-temperature charging performance is acceptable at -10°C, but cycle performance shows significant degradation once temperatures drop to -20°C. Referring to academic research data, the internal resistance of sodium-ion batteries at -20°C can increase by an order of magnitude compared to room temperature, which is a major reason for the suboptimal low-temperature cycling performance.

Another significant pain point is safety. While the industry generally considers the polyanion system to be highly safe, CBAK Energy discovered during development that safety actually tends to decrease as the diameter of the cylindrical battery increases from 26mm to 32mm, 40mm, and even 60mm.

To counter this, the company optimized the anode, electrolyte, and cell structure respectively. Anode optimizations focused on improving the closed-pore structure to reduce side reactions and enhance deintercalation kinetics. For the electrolyte, solvent and additive optimizations were applied to form a stable SEI layer, reducing the exposure of sodium metal clusters and subsequent side reactions with the electrolyte. Structurally, the adoption of a cylindrical full-tab single-pass design provides characteristics of low internal resistance, high-rate capabilities, and excellent heat dissipation. As a result, this battery guarantees a 100% pass rate in nail penetration tests, even within the larger 32 series format.

Spotlight on CBAK Energy’s Sodium-Ion Product Portfolio

Currently, CBAK Energy has developed two flagship sodium-ion batteries based on the 32 series: the NFPP32140NH-7Ah and the layered oxide 32140NS-10Ah. The 32140NH is primarily used in shared battery swapping, portable energy storage, and electric tricycles. The 32140NS is mainly targeted at start-stop systems, AIDC, and UPS applications. Both batteries are currently undergoing customer testing and integration.

The 32140NH features ultra-long cycle performance, a wide operating temperature range, and robust safety. Its cycle life far exceeds conventional industry levels. Although the product specification indicates 6,000 cycles, actual testing at 25°C under a 4C/1C cycle demonstrates a capacity retention of over 92% after 3,000 cycles, with a projected total lifespan of up to 15,000 cycles.

According to relevant experimental data, high temperatures accelerate battery capacity degradation; the degradation rate at 45°C is approximately three times that at 25°C. The 32140NH is projected to exceed 10,000 cycles under a 45°C high-rate cycle. It holds significant application advantages in extreme high-temperature environments. For instance, in regions like Africa with year-round high temperatures where the actual operating environment can reach 70°C, tests indicate the product can achieve an estimated 3,500 cycles at 70°C under 1C/1C conditions. Simultaneously, in low-temperature environments, the discharge retention rate at -40°C is over 85%, and the charge/discharge cycle performance at -10°C remains excellent. It also guarantees a 100% pass rate in stringent safety tests, including nail penetration, overcharging, and crushing.

The 32140NS is a layered oxide sodium-ion battery. This type of layered oxide cathode material is a major research hotspot in the sodium-ion field, and through rational structural regulation, it can achieve ultra-stable electrochemical performance. This battery exhibits a minimal voltage drop during a 20C@3s pulse discharge. The 15C discharge retention rate can reach 91%, and the -40°C low-temperature discharge retention rate reaches 88%, marking an industry-leading level for low-temperature, high-rate performance.

Its cycle performance is equally outstanding. Actual measurements show 2,200 cycles at room temperature (1C/1C) and 1,200 cycles at 45°C (1C/1C). In a -10°C low-temperature environment with a 0.2C/0.5C charge/discharge cycle, capacity retention remains above 95% after 300 cycles.

This sodium-ion battery is primarily geared towards start-stop applications, ensuring a stable power supply even in severe -40°C conditions. In a 180-day float charge test, it demonstrated zero capacity degradation.

From setting durability benchmarks with over 10,000 cycles to pioneering high-rate, low-temperature performance, CBAK Energy will continue to empower diverse application scenarios with its exceptional sodium-ion product matrix. Driven by continuous technological innovation, the company aims to provide the industry with more competitive sodium-ion options and expand into new blue-ocean markets for sodium-ion applications.