Chen Ming, Zhou Qinnan, Iqbal Asma, Liu Xuejiao, Nazakat Ali, Yan Changyu, Tian Heng, Li Wenqian, Zhang Yuchi, Dong Boxu, Zai Jiantao, Qian Xuefeng
Shanghai Electrochemical Energy Devices Research Center, School of Chemistry and Chemical Engineering and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
ACS Appl Mater Interfaces. 2020 Nov 11;12(45):50388-50396. doi: 10.1021/acsami.0c13766. Epub 2020 Oct 27.
The NaTi(PO) (NTP) anode materials exhibit high Na diffusion dynamics; carbon-based materials can effectively improve its limited electronic conductivity. However, the low Na diffusion of NTP/C composite materials from inhomogeneous carbon mixing or uncontrollable carbon coating cannot keep up with fast electron transfer, leading to undesirable electrochemical performances. Herein, a uniform and controllable carbon layer is designed on the self-supported-coated NTP nanorod arrays with binder-free (NTP@C NR) to improve Na and electron kinetics simultaneously. As a result, the NTP@C NR electrodes possess initial coulombic efficiency (ICE = 97%), good rate capabilities (89.1 mA h g at 100 C), and stability with ≈78.4% of capacity retention rate at even 30 C over 1200 cycles. The sodium-ion capacitors with NTP@C NR as an anode and commercially activated carbon as a cathode exhibit ∼9180.0 W kg of power density at 10 A g and super high retention of ≈94.5% at 1 A g over 7000 cycles. This work will help balance transport kinetics between the ion and electron for materials applied in storage devices.
NaTi(PO)（NTP）负极材料具有较高的钠扩散动力学；碳基材料可有效改善其有限的电子导电性。然而，由于碳混合不均匀或碳包覆不可控，NTP/C复合材料的低钠扩散无法跟上快速的电子转移，导致不理想的电化学性能。在此，在无粘结剂的自支撑包覆NTP纳米棒阵列（NTP@C NR）上设计了一层均匀且可控的碳层，以同时改善钠和电子动力学。结果，NTP@C NR电极具有初始库仑效率（ICE = 97%）、良好的倍率性能（100 C时为89.1 mA h g），并且在30 C下经过1200次循环后具有约78.�%的容量保持率的稳定性。以NTP@C NR为负极、商业活性炭为正极的钠离子电容器在10 A g时表现出约9180.0 W kg的功率密度，并且在1 A g下经过7000次循环后具有约94.5%的超高保持率。这项工作将有助于平衡应用于存储设备的材料中离子与电子之间的传输动力学。
