An All-Solid-State Coaxial Structural Battery Using Sodium-Based Electrolyte

Abstract

The transition to a sustainable society is paramount and requires the electrification of vehicles, the grid, industry, data banks, wearables, and IoT. Here, we show an all-solid-state structural battery where a Na+-based ferroelectric glass electrolyte is combined with metallic electrodes/current collectors (no traditional cathode present at fabrication) and thin-ply carbon-fiber laminates to obtain a coaxial multifunctional beam. This new concept aims to optimize the volume of any hollow beam-like structure by integrating an electrochemical system capable of both harvesting thermal and storing electrical energy while improving its mechanical performance. The coaxial cell is a coaxial cable where the dielectric is ferroelectric. The electrochemical results demonstrated the capability of performing three-minute charges to one-day discharges (70 cycles) and long-lasting discharges (>40 days at 1 mA) showing an energy density of 56.2 Wh.L−1 and specific energy of 38.0 Wh.kg−1, including the whole volume and weight of the structural cell. This is the highest specific energy among safe structural cells, while no Na+-based structural cells were found in the literature. The mechanical tests, instead, highlighted the coaxial cell capabilities to withstand severe inelastic deformation without compromising its functionalities, while increasing the flexural strength of the hosting structure. Moreover, the absence of alkali metals and liquid electrolytes together with its enhanced thermal properties makes this coaxial structural battery a valid and safe alternative as an energy reservoir for all the applications where traditional lithium-ion batteries are not suitable.

Giant Polarization in Quasi‐Adiabatic Ferroelectric Na+ Electrolyte for Solid‐State Energy Harvesting and Storage

“…[15] Herein, we show that Na 2.99 Ba 0.005 ClO glass-electrolyte belongs to the family of relaxor-ferroelectric oxides with low resistance (high ionic conductivity), self-charge (negative resistance) [16] , and selfcycling behavior. [8,17] The electrolyte's thermal behavior and thermodynamic, ionic, and electrical properties are multi-coupling features, affecting different parameters related to the battery, such as safety, cycle life, and electrochemical reactions. [18][19][20] Investigation of the thermal behavior of the electrolyte is crucial to improve its performance within the cell.…”

“…Lithium‐ion batteries (LIB) have revolutionized the trend for all electrical applications due to their high energy and power density combination. However, these batteries have quite a few limitations, such as not charging fast enough, having a flammable electrolyte, and having cathodes that tend to reach their theoretical capacity limit [ 8 ] . Researchers worldwide are trying to optimize batteries in terms of efficiency and using sustainable and environmentally friendly materials.…”

Designing Versatile Polymers for Lithium-Ion Battery Applications: A Review

“…Therefore, the challenge relies on the development of a safe solid/gel electrolyte able to efficiently conduct ions (up to ~1 mS·cm −1 ) and withstand mechanical load (shear stiffness between 0.1 and 1 GPa) [ 1 , 182 ]. Another important parameter to achieve is a high Young modulus, which means that if the electrolyte has a low modulus it will not be able to load mechanical transfer between fibers, which is a crucial attribute of the matrix in a structural composite [ 148 ].…”

Cork: Enabler of sustainable and efficient coaxial structural batteries

“…Four main goals upturn when envisioning the perfect battery to become the next-generation powerhouse: (1) it should have a high energy density and (2) store it safely, (3) use environmentally friendly materials and methods, and (4) be widely available and inexpensive. The latter goals depend heavily on the electrolyte used [ 2 , 3 ]. To achieve those objectives, research has turned to all-solid-state batteries, potentially safer than those using a liquid with flammable solvents in the electrolyte formula.…”