Zheng Yongjian, Qiu Wujie, Wang Lei, Liu Jianjun, Chen Shuangqiang, Li Chilin
CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 201899, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Adv Sci (Weinh). 2022 Sep;9(25):e2202201. doi: 10.1002/advs.202202201. Epub 2022 Jul 7.
High-rate anode material is the kernel of developing fast-charging lithium ion batteries (LIBs). T-Nb O , well-known for its "room and pillar" structure and bulk pseudocapacitive effect, is expected to enable the fast lithium (de)intercalation. But this property is still limited by the low electronic conductivity or insufficient wiring manner. Herein, a strategy of triple conductive wiring through electron doping, chelation coating, and electrochemical conversion inside the microsized porous spheres consisting of dendrite-like T-Nb O primary particles is proposed to achieve the fast-charging and durable anodes for LIBs. The penetrative implanting of conformal carbon coating (derivative from polydopamine chelate) and NbO domains (induced by excess discharging) reinforces the global supply of electronically conductive wires, apart from those from Co/Mn heteroatom or O vacancy doping. The polydopamine etching on T-Nb O spheres promotes their evolution into fluffy morphology with better electrolyte infiltration. The synergic electron and ion wiring at different scales endow the modified T-Nb O anode with ultralong cycling life (143 mAh g at 1 A g after 8500 cycles) and high-rate performance (144.1 mAh g at 10.0 A g ). The permeation of multiple electron wires also enables a high mass loading of T-Nb O (4.5 mg cm ) with a high areal capacity of 0.668 mAh cm even after 150 cycles.
高倍率负极材料是发展快速充电锂离子电池（LIBs）的核心。T-NbO因其“房间与支柱”结构和体相赝电容效应而闻名，有望实现锂的快速嵌入和脱出。但这种性能仍受限于低电子电导率或布线方式不足。在此，我们提出一种通过电子掺杂、螯合包覆以及在由树枝状T-NbO初级颗粒组成的微米级多孔球体内进行电化学转化的三重导电布线策略，以实现用于LIBs的快速充电且耐用的负极。除了来自Co/Mn杂原子或氧空位掺杂的导电线外，共形碳涂层（由聚多巴胺螯合物衍生而来）和NbO域（由过放电诱导）的穿透性植入增强了导电线的整体供应。T-NbO球上的聚多巴胺蚀刻促进其演变成具有更好电解质浸润性的蓬松形态。不同尺度下电子和离子布线的协同作用赋予改性T-NbO负极超长循环寿命（在1 A g下8500次循环后为143 mAh g）和高倍率性能（在10.0 A g下为144.1 mAh g）。即使在150次循环后，多条电子线的渗透也能实现T-NbO的高负载量（4.5 mg cm）和0.668 mAh cm的高面积容量。
