Integration of 3D-printed electrolyte for low self-discharge woven carbon fiber-based structural battery with porous LiNi0.90Al0.06Ti0.02Mg0.02O2 cathode

Abstract

Structural batteries fabricated from woven carbon fiber are well-known for their excellent dual functionality of load bearing and energy storage capacity, making them suitable for applications in automobiles, aerospace, and portable electronics. In this study, we developed a woven carbon fiber structural battery using a LiNi0.90Al0.06Ti0.02Mg0.02O2 nanoporous material coated on the fiber as the cathode, graphene oxide-coated carbon fiber as the anode, and a PVDF-coated Kevlar fiber separator. The electrolyte was integrated into the device using a 3D printing method, a notably easy, cost-effective, and time-saving approach. The nanoporous material significantly enhances the surface area of the carbon fiber cathode, up to 354 m2/g. The energy density of the battery is recorded as 48.4 Wh/kg at 0.1C, with a high tensile strength of 716.29 MPa and a modulus of 18.92 GPa. The device exhibits a significant ionic conductivity of 7.81 x 10-5 S/cm, achieved through the combination of MXene with EMIMBF4 ionic liquid and LiTf salt in a polyester-based electrolyte. Quantitative analysis of the reaction kinetics of the battery suggests a predominance of capacitive control over diffusion-controlled current. The battery demonstrated high cyclic stability, with 82 % capacity retention and 97 % coulombic efficiency after 1500 charge-discharge cycles. The device also performs under high external stress, maintaining 65 % of its capacity after being subjected to a stress of 500 MPa and subsequently released. The low leakage current of the battery indicates its resistance to self-discharge, with the battery retaining 90 % of its capacity after 150 days. Even at 50 degrees C, the battery performs well, showcasing its thermal stability. Overall, the battery demonstrates excellent performance in various aspects, making it suitable for integration into a wide range of multifunctional products.