Abstract
The printing of three-dimensional (3D) porous electrodes for Li-ion batteries is considered a key driver for the design and realization of advanced energy storage systems. While different 3D printing techniques offer great potential to design and develop 3D architectures, several factors need to be addressed to print 3D electrodes, maintaining an optimal trade-off between electrochemical and mechanical performances. Herein, we report the first demonstration of 3D printed Si-based electrodes fabricated using a simple and cost-effective fused deposition modelling (FDM) method, and implemented as anodes in Li-ion batteries. To fulfil the printability requirement while maximizing the electrochemical performance, the composition of the FDM filament has been engineered using polylactic acid as the host polymeric matrix, a mixture of carbon black-doped polypyrrole and wet-jet milling exfoliated few-layer graphene flakes as conductive additives, and Si nanoparticles as the active material. The creation of a continuous conductive network and the control of the structural properties at the nanoscale enabled the design and realization of flexible 3D printed anodes, reaching a specific capacity up to ∼345 mA h g−1 at the current density of 20 mA g−1, together with a capacity retention of 96% after 350 cycles. The obtained results are promising for the fabrication of flexible polymeric-based 3D energy storage devices to meet the challenges ahead for the design of next-generation electronic devices.
Highlights
IntroductionThe application of Li-ion batteries has grown exponentially in recent decades due to the increasing demand for different emerging technologies, e.g., portable electronics and plug-in hybrid electric vehicles.[1,2] The increasing interest in Li-ion battery technology mainly relies on their high energy density (e.g., 150–270 W h kgÀ1),[3] low self-discharge (between 0.35% and 2.5% per month, depending on the state of charge),[4] and stable cyclic performance.[5,6,7] To ful l the growing demand for advanced Li-ion batteries, great efforts have been dedicated to the development of new electrode materials capable to improve the energy capacities and lifetimes of the currently available technologies.[8,9] Graphite, commonly used as the anode material in prototypical Li-ion batteries, has a limited theoretical capacity of 372 mA h gÀ1.10 several alternatives to graphite have been widely investigated,[11,12,13,14,15] among which silicon (Si) has been demonstrated to be an excellent candidate thanks to its extraordinary theoretical capacity of 4200 mA h gÀ1
We report the first demonstration of 3D printed Si-based electrodes fabricated using a simple and cost-effective fused deposition modelling (FDM) method, and implemented as anodes in Li-ion batteries
The electrochemical impedance spectroscopy (EIS) results indicate that the cyclic stability and high-rate capabilities of the printed electrodes strongly depend on the formation of a 3D conductive wet-jet milling-exfoliated few-layers graphene (WJM-FLG) and carbon black-doped PPy-based network that con nes the Si nanoparticles.[18,81]
Summary
The application of Li-ion batteries has grown exponentially in recent decades due to the increasing demand for different emerging technologies, e.g., portable electronics and plug-in hybrid electric vehicles.[1,2] The increasing interest in Li-ion battery technology mainly relies on their high energy density (e.g., 150–270 W h kgÀ1),[3] low self-discharge (between 0.35% and 2.5% per month, depending on the state of charge),[4] and stable cyclic performance.[5,6,7] To ful l the growing demand for advanced Li-ion batteries, great efforts have been dedicated to the development of new electrode materials capable to improve the energy capacities and lifetimes of the currently available technologies.[8,9] Graphite, commonly used as the anode material in prototypical Li-ion batteries, has a limited theoretical capacity of 372 mA h gÀ1.10 several alternatives to graphite have been widely investigated,[11,12,13,14,15] among which silicon (Si) has been demonstrated to be an excellent candidate thanks to its extraordinary theoretical capacity of 4200 mA h gÀ1. By engineering the doping of PPy with carbon black, the printable lament achieves an electrical conductivity as high as 5.19 S cmÀ1, which is 9 order of magnitude higher than conductivity of the bare PLA lament, and only one order of magnitude superior to the conductivity reported for conductive laments produced through FDM 3D printing (e.g., 0.4 S cmÀ1).[26] The distinctive electrical properties reached by our lament allow us to print 3D exible polymeric anodes for Li-ion batteries As assessed for both pristine graphene and its derivatives (e.g., functionalized reduced graphene oxide),[49,50,51,52,53,54,55] the WJM-FLG create inter-layered structures that provide transport channels for electrons and ions, improving the electrical and ionic (Li+) conductivity compared to the reference (i.e., WJM-FLG-free) electrodes.[56] both WJM-FLG and doped PPy uniformly coat the surface of the Si nanoparticles, limiting the volumetric expansion of electrodes during Si lithiation.[19,57] the conductive WJM-FLG/ doped PPy network effectively surrounds the Si nanoparticles to prevent the volume change upon the de-lithiation, avoiding aggregation effects that degrade the anode performances. Our results prove the possibility to speci cally use the FDM method as low-cost and highspeed 3D printing technique, simplifying the scaling-up of the electrode manufacturing compared to other 3D printing technologies
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
