Carbon quantum dot‐laminated stepped porous Al current collector for stable and ultrafast lithium‐ion batteries
Ki‐Wook Sung, Kue‐Ho Kim, Hyo‐Jin Ahn
Abstract
Designing an interfacial architecture between the current collector and electrode plays a serious role in developing the specific capacity with cycling stability of lithium-ion batteries (LIBs). Consequently, an original approach to enhance the structure of the interface between the current collector and electrode is necessary. Thus, we developed a novel interface architecture based on carbon quantum dots (CQDs)-laminated on a stepped porous Al (SP-Al) current collector to attain stable and ultrafast-discharge LIBs and CQD-SP-Al for application as LIB cathodes. To this end, the electrochemical etching and ultrasonic spray coating methods were employed. The cathode assembled with CQD-SP-Al displayed the adhesion enhancing, an increased redox reaction kinetics, and the magnificent interfacial stability of the current collector//electrode interface because of the increased surface roughness, stepped pores with N-doped CQD, and uniform CQD lamination layer. The resultant cathode with CQD-SP-Al showed an enhanced specific capacity of 78.2 mAh/g and capacity retention of 92.6% at a high C-rate of 10C after 500 cycles. This great cycling stability is due to an expanded interfacial contact area of current collector//electrode with improved adhesion, as well as to the CQD lamination layer, while the excellent ultrafast discharge capacity is ascribed to the risen number of charge supplying/collecting sites, the stepped porous structure, and the highly conductive N-doped CQD lamination layer.