Converting waste biomass into biochar is a means for solving both environmental pollution and energy shortage. Here we transformed Eichhornia crassipes, a harmful floating plant, into a honeycomb-shaped and heteroatoms-rich biochar by KOH activation during carbonization, and we tested this biochar as anode for lithium-ion batteries. Results show that the biochar has a high surface area of 278.56 m²·g⁻¹, a honeycomb-like porous structure, and is rich in heteroatoms, e.g., 3.42% N, 20.82% O, and 0.83% S. Biochar anodes displayed a higher initial reversible specific capacity of 697 mAh·g⁻¹ at 50 mA·g⁻¹, a higher rate capability of 229.7 mAh·g⁻¹ at 3000 mA·g⁻¹, and a better cyclic stability than commercial graphite. The enhanced electrochemical performance could be attributed to the interconnected porous structure that promotes Li⁺ transfer and electrolyte infiltration, and to the presence of heteroatoms. This approach can be easily industrialized as a substitute of graphite.

将废物生物质转化为生物碳是解决环境污染和能源短缺的一种手段。在这里，我们通过碳化过程中的KOH活化作用，将有害的漂浮植物凤眼莲（Eichhornia crassipes）转变为蜂窝状且富含杂原子的生物炭，并测试了该生物炭作为锂离子电池的负极。结果表明，该生物炭具有278.56 m ² ·g ^-1的高表面积，呈蜂窝状的多孔结构，并富含杂原子，例如3.42％N，20.82％O和0.83％S。 697毫安的较高的初始可逆比容量·^克-1在50mA·^克-1，229.7毫安^·g的较高的速率能力^-1在3000毫安·^克-1，并具有比市售石墨更好的循环稳定性。增强的电化学性能可以归因于促进Li ⁺转移和电解质渗透的互连多孔结构，以及杂原子的存在。这种方法可以很容易地工业化以替代石墨。