Research on Structural Regulation of Hard Carbon Anode Materials and Their Application in Sodium-Ion Batteries — Prof. Chenghao Yang, Guangdong Rongna New Energy

Carbon neutrality is driving sustained rapid growth of new-energy vehicles and energy-storage batteries globally over an extended period. As sodium-ion battery manufacturing technologies continue to advance, sodium-ion batteries are poised for broader development opportunities, with their application scope expanding continuously across energy storage, electric vehicles, and other fields. Although sodium-ion batteries have relatively low energy density, their cost advantage makes them promising candidates for applications where energy density requirements are modest but cost sensitivity is high—such as grid-scale energy storage, low-speed transportation, and certain short-range passenger vehicles—thus offering vast future market potential. However, currently, the high cost of hard carbon anode materials severely constrains the pace of sodium-ion battery development. Therefore, Guangdong Rongna New Energy aims to develop high-performance, cost-effective hard carbon materials to accelerate industry-wide progress. Currently, precursors for hard carbon anodes are diverse and include biomass, resin-based materials, and pitch. Japan’s Kuraray uses coconut shells—a biomass material—as its hard carbon precursor. Domestic traditional lithium-ion battery anode manufacturers—including BTR, Shanshan, Zhongke Xingcheng, and Xiangfenghua—employ a range of precursors such as biomass-derived feedstocks, resins, and pitch-based materials, achieving systematic patent layouts. Best-Graphite, a hard carbon anode company positioned as a domestic counterpart to Kuraray, focuses on preparing hard carbon from biomass precursors including glucose, starch, lignin, and coconut shells. Yuanli Co., Ltd. utilizes raw materials such as moso bamboo, coconut shells, and rice husks. Shengquan Group employs straw. Wuhan Bixidi selects phenolic resin as its precursor. During market research, Rongna New Energy found that biomass precursors were the earliest used for hard carbon synthesis; however, domestic production capacity remains insufficient, resulting in heavy reliance on imports. Thus, developing alternative biomass feedstocks holds significant economic value. Resin-based products offer excellent consistency but at relatively higher costs. Pitch is abundantly available, yet current processing technologies remain immature and yield relatively low capacities. · [Sodium Storage Mechanism in Hard Carbon and Electrolyte Selection] Rongna New Energy has also conducted research into the sodium storage mechanism of hard carbon and electrolyte selection. Regarding the sodium storage mechanism in hard carbon, three primary mechanisms exist: surface adsorption, interlayer intercalation, and minor pore-filling at the surface (which is negligible). Hence, the dominant mechanisms can be broadly categorized into two: surface adsorption and interlayer intercalation. Prof. Chenghao Yang’s research team discovered that the sodium-ion intercalation energy barrier in hard carbon decreases as the interlayer spacing (d002) increases within the range of 0.35–0.5 nm. However, when d002 exceeds 0.42 nm, sodium storage occurs predominantly via surface adsorption (pseudocapacitive behavior). The optimal interlayer spacing for hard carbon lies between 0.37–0.42 nm.

China Hard Carbon Anode Material Market Development and Investment Outlook Forecast Research Report (2026 Edition)

Anode materials constitute one of the key components governing the technological advancement and practical application of sodium-ion batteries. Due to the significantly larger ionic radius of sodium compared to lithium, sodium-ion insertion/extraction induces substantial structural changes in electrode materials, leading to reduced reversible capacity. Moreover, graphite—anode material widely used in lithium-ion batteries—exhibits poor sodium storage performance due to thermodynamic limitations, presenting major challenges in developing viable sodium-ion battery anodes. Similar to lithium-ion batteries, sodium-ion batteries operate on a ‘rocking-chair’ charge/discharge principle; thus, their anode requirements share certain commonalities. An ideal sodium-ion battery anode material should satisfy seven critical criteria: high specific capacity, low voltage hysteresis, good rate capability, long cycle life, high initial Coulombic efficiency, scalable manufacturability, and cost-effectiveness. Carbon-based anode materials currently dominate the sodium-ion battery anode landscape. During charging/discharging, sodium-ion batteries rely on anode materials as the primary host for sodium-ion storage, enabling reversible sodium-ion intercalation/deintercalation. The choice of anode material directly determines the electrochemical performance of the battery. Currently, promising sodium-ion battery anode candidates include carbon-based materials (e.g., graphite, graphene, hard carbon, soft carbon), alloy-based materials, metal/sulfide compounds, titanates, metal oxides, and other organic compounds. Among these, carbon-based sodium-storage anode materials—including graphite, graphene, hard carbon, and soft carbon—stand out due to their low sodium-insertion plateaus, high capacity, long cycle life, simple synthesis, environmental friendliness, and non-toxicity. Other material systems face constraints such as prohibitively high costs and difficulties in large-scale production relative to carbon-based alternatives; consequently, carbon materials remain the predominant anode choice for sodium-ion batteries. From a commercial perspective, most leading battery manufacturers opt for hard carbon anodes. Hard carbon is typically synthesized by pyrolyzing oxygen-rich (hydrogen-deficient) precursors—such as resins, biomass, coal-based feedstocks, or pitch—at temperatures exceeding 1000 °C. Multiple synthetic routes coexist in hard carbon production, with anode manufacturers pursuing distinct technical strategies. Japan’s Kuraray uses coconut shells (a biomass precursor); domestic lithium-ion battery anode giants—including BTR, Shanshan, Zhongke Xingcheng, and Xiangfenghua—employ biomass-derived, resin-based, and pitch-based precursors, establishing comprehensive patent portfolios. Best-Graphite, aiming to rival Kuraray, specializes in hard carbon derived from glucose, starch, lignin, and coconut shells. Yuanli Co., Ltd. sources moso bamboo, coconut shells, and rice husks. Shengquan Group utilizes straw. Wuhan Bixidi adopts phenolic resin. According to publicly disclosed patent information from Shanshan Technology and BTR, hard carbon synthesis processes using both pitch-based and resin-based precursors have already been successfully developed. Hard carbon anode cost accounts for a higher proportion of total battery cost than lithium-ion battery anodes. In layered oxide cathode-based sodium-ion batteries versus lithium-ion batteries, the main cost differences lie in cathode and anode materials. According to calculations by HiNa Battery Technology, the anode contributes approximately 16% of total raw material costs in sodium-ion batteries—significantly higher than the ~11% contributed by anodes in lithium-ion batteries. Consequently, reducing anode material costs is a pivotal lever for lowering overall sodium-ion battery costs—and a core component of sodium-ion batteries’ cost competitiveness against lithium-ion alternatives. Regarding hard carbon anode demand, it is projected to reach 162,300 tons by 2026, corresponding to a market size potentially exceeding RMB 7.3 billion. "China Hard Carbon Anode Material Market Development and Investment Outlook Forecast Research Report (2026 Edition)" Prepared by: Shenzhen Desuanduo Consulting Co., Ltd.

Stora Enso, Shanshan Technology Team Up on Lignin-Based Hard Carbon Anodes

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Stora Enso and Shanshan Technology announced a partnership to develop lignin-based hard carbon anode materials for sodium-ion batteries. A demonstration line will be built in Ningbo to accelerate technical development and commercialization.

chemweek

2026-10-29

Stora Enso, Shanshan Technology Team Up on Lignin-Based Hard Carbon Anodes

Stora Enso, Shanshan Technology Team Up on Lignin-Based Hard Carbon Anodes

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