Flexible zinc-ion hybrid supercapacitors with printable liquid GaInZn alloy anode

Abstract

In the realm of wearable electronics, the advancement of flexible energy storage hinges critically on the innovation of efficient electrodes. However, traditional zinc anodes employed in zinc-ion hybrid supercapacitors (ZIHSCs) exhibit restricted flexibility. In this study, we fabricated a novel GaInZn alloy anode. Through the precise melting of Ga, In, and Zn in exact proportions and subsequent deposition onto a flexible substrate via a printing technique. The liquid GaIn phase, with its unique characteristics, uniformly coats the anode surface, thereby optimizing the local electric field and ion current distribution and effectively inhibiting the growth of zinc dendrites. Facilitated by its relatively low melting point, the application onto the flexible substrate is facilitated. The assembled GaInZn//PAM//AC device, featuring an alloy with a mass ratio of m_Ga/m_In/m_Zn = 3/5.6/1.4, demonstrated exceptional performance, achieving 88 % capacity retention after 3000 cycles. It also delivered an impressive energy density of 54.5 Wh kg⁻¹ at a power density of 287.2 W kg⁻¹. Moreover, repeated bending tests revealed excellent mechanical stability, with the device retaining 80.8 % of its initial capacity even after 800 bending cycles. This printable liquid alloy anode holds substantial promise for the next-generation flexible energy storage within the realm of wearable electronics.