生物法回收电池关键金属研究进展

With the rapid expansion of lithium-ion battery (LIB) production driven by the global energy transition, the disposal of end-of-life batteries has emerged as a critical challenge due to resource depletion and environmental hazards. Conventional pyrometallurgical and hydrometallurgical recycling methods, while dominant, face significant drawbacks such as high energy consumption (exceeding 1000 ℃ for pyrometallurgy), substantial carbon emissions (about 3.5 tons CO₂/ton of batteries), and toxic wastewater generation (pH<2, 2～3 tons/ton of batteries), underscoring the urgent need for sustainable alternatives. Biological recovery technologies, leveraging microbial metabolic activities, have gained prominence as eco-friendly, low-cost solutions for reclaiming strategic metals like lithium, cobalt, nickel, and manganese. This review systematically examines four core biotechnological approaches—bioleaching, biosorption, bioaccumulation, and biomineralization—detailing their mechanisms, advancements, and industrial scalability. Bioleaching, facilitated by acidophilic bacteria (e.g., Acidithiobacillus ferrooxidans, A. thiooxidans) and fungi (e.g., Aspergillus niger), employs microbial metabolites such as organic acids (citric, gluconic) and Fe³⁺/H₂SO₄ to dissolve metal oxides from battery “black mass,” achieving recovery rates of 60%～80% for Li and 85%～90% for Co/Ni under optimized conditions (30～40 ℃, pH 1.5～3.0). Innovations in fungal strain engineering and co-culture systems (e.g., sulfur- and iron-oxidizing bacteria) have enhanced leaching kinetics and metal selectivity, while response surface methodology (RSM) has optimized parameters like pulp density (1∶5～1∶10) and aeration (1 L/min). Biosorption exploits functional groups (e.g., carboxyl, amino) on microbial cell walls to immobilize metal ions via electrostatic interactions, with engineered strains like Escherichia coli expressing metallothioneins demonstrating 7-fold higher Ni²⁺ uptake. Bioaccumulation, enabled by synthetic biology, focuses on intracellular metal transport systems, such as NikABCDE transporters, though challenges like metabolic burden and metal toxicity persist. Biomineralization harnesses microorganisms (e. g., sulfate-reducing bacteria) to precipitate dissolved metals as stable minerals (e. g., MnCO₃, NiS), which can be directly converted into electrode materials. For instance, fungal-synthesized MnCO₃derived MycMnO_x/C composites exhibit exceptional supercapacitor performance (>350 F/g) and LIB cycling stability (>90% capacity retention after 200 cycles). Despite these advances, bottlenecks remain, including prolonged leaching cycles, scalability limitations, and the need for genetic engineering to enhance microbial metal tolerance and acid production. Emerging strategies, such as CRISPR-Cas9-mediated pathway optimization, biomimetic ion channels (e.g., NH₂-pillar[5]arene for Li⁺ selectivity), and hybrid biohydrometallurgical processes, promise to bridge these gaps. Coupled with policy incentives and declining operational costs (projected at $1000～2000/ton, 25%～40% lower than hydrometallurgy), bio-recovery technologies are poised to revolutionize the LIB recycling industry, aligning with circular economy principles and achieving near-zero carbon emissions (<0.5 tons CO₂/ton of batteries). Future research should focus on the convergence of synthetic biology, materials science, and process engineering to achieve industrial-scale implementation, ultimately fostering a truly sustainable and resilient battery supply chain.