The Future of Battery Recycling: Patent Analysis of Hydrometallurgical Technology for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have become a central technology in energy storage since their commercialization in the 1990s by Sony.  

A lithium-ion cell consists of six main components that must all be recovered during the recycling process (see Figure 1). The anode and cathode are electrochemically active materials, while the separator electrically isolates the two electrodes. 

Battery specialists have defined generations of technology that have succeeded each other continuously since Sony's first LCO battery in 1991: 

• Generation I (before 2010): LCO cathodes – graphite anode.
• Generation II (2010-2020): NCA/NMC 111 cathodes – graphite anode.
• Generation III (2020-): Low-cobalt cathodes (NMC622-NMC811) – silicon-enriched anodes.
• Generation IV (2030?): All-solid lithium metal batteries – cobalt-free oxides. 

Recycling used batteries not only aims to reduce environmental impact but also focuses on recovering valuable components from electronic waste. 

By 2040, it's estimated that recycling could provide 51% of the cobalt, 42% of the nickel, and 23% of the manganese used in battery production within the European Union. However, only 9% of lithium is expected to come from secondary sources. 

In response to the increase in LIBs production and the challenge of managing end-of-life batteries, several recycling technologies have been developed.  

The three main approaches are pyrometallurgy, hydrometallurgy, and direct recycling: 

Hydrometallurgical technology uses acidic solutions to extract valuable metals like lithium, cobalt, and nickel when recycling LIBs. The process involves grinding used batteries and dissolving metals with acids (e.g., H₂SO₄ or HCl) and reducing agents, enabling high-purity recovery and better selectivity compared to thermal methods. 

In terms of innovation, efforts are focused on developing "Hydro 4.0," a concept aimed at making processes more environmentally friendly and automated by integrating advanced technologies such as data analytics and machine learning. 

• Innovations

Companies and research institutions are investing in patented hydrometallurgical recycling technologies capable of processing various battery chemistries (LFP, NMC, LCO, etc.), thereby ensuring process flexibility. 

• 1. Integration of Electrodialysis: Researchers at the University of Malaga have proposed using electrodialysis in hydrometallurgical recycling processes. This approach aims to improve the separation and recovery of valuable metals from spent batteries. It aligns with a circular economy logic by optimizing resource recovery while reducing environmental impact. However, challenges remain, particularly regarding energy consumption and system optimization.
• 2. Selective Leaching Technologies: Innovations in selective leaching aim to maximize metal extraction while reducing the use of reagents and waste production. These processes target critical metals with high efficiency and seek to make recycling both economically viable and sustainable. The challenge is to reconcile economic performance with reduced environmental impact by optimizing the chemistry used and the reaction conditions.
• 3. Hydrometallurgical Recycling via Biodegradable Acid Leaching: This innovation employs a mixed leaching system using biodegradable acids, including ascorbic acid and citric acid, to extract metals from spent batteries. Proposed by Fatima et al. (2024) through use of non-toxic and environmentally responsible reagents. 
   

Each of these three recycling technologies plays a vital role in managing lithium-ion batteries sustainably. Pyrometallurgy is effective for large-scale processing but has a high ecological footprint. Direct recycling could further reduce environmental impact, especially as battery standardization improves. Future hybrid processes, along with stricter regulations, will likely drive innovation and support a circular economy as demand for batteries continues to grow. Hydrometallurgy offers a balanced approach with better efficiency and sustainability, making it the most promising method for EV batteries, though it requires careful chemical waste management. This is why the following patent landscape analysis focuses on this technology. 

Patent landscape analysis offers valuable insight into innovation, including helping us to predict the future of technology. In this part, we will share what our patent landscape analysis of innovation in hydrometallurgical lithium-ion battery recycling can tell us about the next generation of this technology, including the major industry players and main research and development (R&D) markets behind this innovative solution.  

To understand the innovation and R&D activities in this technology, we performed a macro search using our proprietary IP intelligence software. By analyzing the patents collected using our IP Consulting services expertise, we were able to create a fascinating global insight into research advancement and investment in this field.   

In total, the database comprises 2,958 patent families filed in the last 20 years.  Patent filing dynamics reveal a significant rise in patent activity related to hydrometallurgical Li-ion battery recycling from 2004 to 2024, with a sharp increase starting from 2017. 

Early years exhibit relatively low patent filings, however, starting from 2017, there has been a significant surge. By 2020, the number of granted patents peaked at 190, marking a 144% increase from the 78 patents granted in 2017. Similarly, the number of pending patents increased substantially from just 4 in 2017 to 127 in 2021, reflecting an exponential growth (as shown below). 

This surge is driven by rising demand in electric vehicles, consumer electronics, and energy storage, along with an emphasis on sustainable recycling to manage battery waste and recover materials essentially lithium, cobalt, and nickel for the green transition. 

Our patent landscape analysis reveals the key players in the hydrometallurgical recycling of Li-ion batteries field. 

• Sumitomo Metal Mining Co. Ltd., a leading Japanese mining and smelting company, holds 79 granted patents and 21 pending patents, reflecting a robust intellectual property portfolio in the field. The company has made significant strides in hydrometallurgical recycling of LIBs focusing on environmentally friendly processes to efficiently recover valuable metals like lithium, cobalt, and nickel. Its innovations, including enhanced solvent extraction methods, aim to improve metal recovery effectiveness while minimizing environmental impact, promoting a sustainable approach to battery recycling.
   
• Hunan Brunp Recycling Technology and Guangdong Brunp Recycling technology, both subsidiaries of the leading Chinese battery manufacturer CATL (Contemporary Amperex Technology Co., Ltd.), specialize in the recycling of LIBs. Hunan Brunp focuses on dismantling and hydrometallurgical processing of spent batteries, while Guangdong Brunp concentrates on recovering key metals. With 45 and 44 granted patents, respectively, along with 47 pending patents, these companies are advancing recycling technologies and reinforcing China’s commitment to leadership in the circular economy for LIBs. The limited number of expired patents suggests that their innovations remain highly relevant and at the forefront of the rapidly evolving battery recycling sector.
   
• Central South University and Institute of Process Engineering, Chinese Academy of Sciences are leading academic institutions contributing significantly with 35 granted patents, and 31 pending patents for Central South University and 25 granted patents for the Institute of Process Engineering. Their contribution underscores the importance of research institutions in innovating sustainable recycling technologies, particularly in China.
   
• BASF is one of the largest chemical companies in the world, with 27 pending and 7 granted patents, it represents a significant European player. Collaborating with industry leaders like Iveco Group and Stena Recycling, BASF advances electric vehicle battery recycling processes, prioritizing resource efficiency and sustainability. Meanwhile, its North American partnership with Nanotech Energy focuses on reducing CO₂ emissions by producing lithium-ion batteries that incorporate recycled materials. Through ongoing collaborations with academic institutions, BASF continues to drive innovation in battery materials, reinforcing its commitment to sustainable solutions in energy storage.
   
• JX Nippon Mining & Metals (58 granted patents, 4 pending patents, and 11 expired patents) alongside its recycling-focused subsidiary JX Metals Circular Solutions (27 granted patents) showcases Japan’s technological leadership in advanced metal recovery and recycling from lithium-ion batteries. These innovations, strengthened by a partnership with Mitsubishi Materials, which holds 10 granted patents, provide closed-loop recycling solutions for electronic and automotive waste, aiming to secure a stable supply of recycled materials while supporting Japan’s commitment to a circular economy and global decarbonization goals in the battery and electronics industries.
   
• Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA) holds a moderate portfolio of 14 granted patents and 4 pending patents. This focus aligns with its mission as a French public research organization to advance sustainable technologies and contribute to France’s circular economy goals. For lithium-ion batteries, CEA emphasizes the treatment and recycling of lithium, cobalt, manganese, and nickel. 

Priority country filing most often occurs in the country in which the research and development (R&D) takes place, so looking at this data shows us which countries are the most innovative and which are the ones that seek to protect their inventions. 

The geographic distribution of patents in hydrometallurgical technology for recycling lithium-ion batteries reveals that the majority of activity is concentrated in China. 

• China (CN) shows a significant increase in patent applications over the years, particularly from 2016 onwards, already reaching a peak of 473 patent families in 2023 even though the year might be incomplete. This trend highlights China’s strong focus on LIBs recycling, driven by its extensive battery production and consumption. Such leadership in patent filings reflects China's dominance in the global battery supply chain and its growing focus on recycling technologies.
   
• Japan (JP) has a steady increase in patent filings, peaking between 2018 and 2021. This trend reflects Japan’s focus on securing resources like lithium and cobalt through recycling, given its limited domestic supply. Japan’s commitment to innovation in recycling technologies aligns with its strategic goals for resource security and environmental sustainability.
   
• World Organization (WO) patent applications show a gradual increase, peaking around 2020-2023. This trend indicates a growing international interest and active innovation in this field. 
   
• United States (U.S.), South Korea (KR), and Europe (EP) exhibit moderate but steady growth in patent filings, highlighting their roles in the global battery recycling industry. The U.S. and South Korea show consistent filings, peaking around 2020-2022. The heatmap indicates an upward trend in filings since 2010, with rapid growth from 2018-2022, driven by rising demand for LIB in electric vehicles, electronics, and renewable energy, along with the need for sustainable disposal solutions. 

• China leads significantly with over 1,800 patent families, of which 712 are granted and 730 are pending, showcasing the country’s dominance and commitment to this field.  
  
  This aligns with China’s push for sustainability, reflected in the production of 9.3 million EVs in 2023 (65% of global production) and the sale of 8.4 million units, 59% of global sales, with approximately 90% of those sales being domestic in 2023 (source). The scale of EV production and consumption establishes China as a primary market for LIB recycling, driving advancements in eco-friendly and efficient metal recovery methods. 
   
• Japan demonstrates strong activity with 240 granted patents and 92 pending applications. Japan’s commitment to innovation in LIB recycling is evident, signaling a robust pipeline of advancements in sustainable battery management. 
   
• The United States (U.S.) shows a proactive approach, with 59 granted patents and 117 pending patents, U.S. efforts focus on refining recycling processes, exploring novel methods like deep eutectic solvents for metal extraction, and developing scalable solutions to address growing battery waste. One such innovation is Aqua Metals’ patent-protected AquaRefining™ process, which was initially applied to lead recycling and is now being extended to lithium-ion battery processing. This method, which utilizes water at ambient temperature, reduces pollutant emissions and enables efficient recovery of metals. However, despite its environmental benefits, large-scale commercialization of this patent-protected technology remains a challenge. 
   
• South Korea (KR) presents a considerable patent activity, with 124 granted patents and 57 pending patents, reflecting a strategic focus on resource recovery and green technology. Government-supported R&D and academic-industry collaborations aim to enhance recycling efficiency and reduce reliance on imported raw materials. 
   
• Europe (EP), with 14 granted patents and 56 pending patents, has shown a marked increase in patent activity for hydrometallurgical technology for battery recycling. This trend aligns with EU policies promoting sustainable technology and reducing electronic waste, making hydrometallurgical recycling a priority for both environmental and economic reasons across Europe. 
   
• Other countries, like India, show smaller numbers of patents, likely indicating emerging or more niche interest in this field. 

Hydrometallurgical technology for battery recycling offers a promising path forward in the sustainable management of lithium-ion batteries. By using chemical processes to recover valuable metals like lithium, cobalt, and nickel, this approach can efficiently reclaim high-purity materials, which is crucial for meeting the growing demand driven by electric vehicles, consumer electronics, and renewable energy storage systems. 

The surge in patent activity related to hydrometallurgical recycling highlights the increasing global focus on developing innovative and cost-effective solutions. Countries like China and Japan are leading the way, driven by ambitious regulations and strategic goals to secure essential raw materials through recycling. Major industry players and research institutions are actively exploring new techniques, such as selective leaching and the integration of advanced technologies, to improve efficiency and reduce environmental impact. 

Recent trends also show growing interest in collaborative efforts between industry and academia, emphasizing the importance of continued innovation to address the challenges of battery waste. With advances in automation and eco-friendly processes, the future of battery recycling appears bright. As regulatory frameworks strengthen globally, supporting circular economy principles, hydrometallurgical recycling will likely play a critical role in reducing our dependence on mining and creating a more sustainable energy landscape. 
 
Patent landscape analysis can provide valuable insights into research and innovation trends and markets, as we hope this analysis of hydrometallurgical LIBs recycling illustrates. For further details on patent activity in this sector or for specific advice or support on any other topic, contact the Questel IP Consulting team.