ALD modification enabled high voltage reliable asymmetric supercapacitor

events hall

Mr. Chongrui Wu, M.Sc. Candidate




Lithium-ion capacitor (LIC) has attracted much attention in recent years as a novel energy storage device. It has a superior power density and a better cycle life performance than conventional lithium-ion batteries (LIB) and a higher energy density as well as larger voltage windows than electrical double-layer capacitors (EDLCs). EDLCs based on activated carbon (AC) electrodes suffer from instability at high working voltages, while Li-rich manganese nickel oxide (LMNO) electrodes are subjected to HF-attack and a generation of cathode electrolyte interphase (CEI) issue. Herein, we introduce an atomic layer deposition (ALD) of aluminum oxide and zinc oxide to improve the stability of these electrodes under higher working voltages in organic electrolytes. The ALD processing conditions on AC electrodes are optimized to form a conformal coating of nanometer metal oxide. This coating strategy is designed to enable AC electrodes to be better compatible with LMNO electrodes for a full asymmetric capacitor design which provides higher voltage windows, enhanced discharge capacity, and better cyclic life stability. To assess the ALD coating approach, we performed extensive electrochemical testing and microstructural characterization. The enhanced electrochemical performance of AC and LMNO electrodes separately proves the effectiveness of the coating tactics. Subsequently, we will discuss the construction of an asymmetric lithium-ion capacitor using the ALD modified anode and cathode to demonstrate the high working voltage and long cyclic life.

Supervisor: Prof. Yair Ein-Eli, Prof. Daniel Tan

Seminar via ZOOM