大容量锂离子电容器用锂化硬炭负极

High Energy Lithium Ion Capacitor with Pre-Lithiated Hard Carbon Anode

采用硬炭与锂源自放电这种简单的预锂化方法可使锂嵌入硬炭,而后以预锂化硬炭和活性炭分别为负极和正极组装了锂离子电容器,研究了负极预锂化时间对锂离子电容器比容量的影响,结果表明随着预锂化时间的延长,比容量先增大后减小,15 h为最适宜预锂化时间。经过15 h预锂化的锂离子电容器具有最高的能量密度(97.2 Wh·kg-1)和功率密度(5 412 W·kg-1)、最小的阻抗和良好的循环性能(1 A·g-1的电流密度下循环1 000次后,能量保持率为91.2%)。三电极数据表明锂离子电容器优异的电化学性能源于正负极材料各自处于合适的工作电压区间。

Pre-lithiated hard carbon can be obtained by short-circuiting hard carbon anode and lithium sources. Then a lithium ion capacitor is fabricated with the pre-lithiated hard carbon anode and activated carbon cathode. The pre-lithiation time of anode has a great effect on the capacity of lithium ion capacitor. The capacity firstly increases and then decreases with increasing the pre-lithiation time and 15 h is the optimal pre-lithiation time. The capacitor with 15 h pre-lithiation has the maximum specific energy( 97. 2 Wh·kg- 1),maximum specific power( 5 412 W·kg- 1),minimum resistance and superior cycle performance with an energy retention of 91. 2% even after 1 000 cycles at the current density of 1 A·g- 1.The outperforming performance is ascribed to the proper working potential of both anode and cathode according to the three electrode data.