Formate: an Energy Storage and Transport Bridge between Carbon Dioxide and a Formate Fuel Cell in a Single Device

Abstract

We demonstrate the first device to our knowledge that uses a solar panel to power the electrochemical reduction of dissolved carbon dioxide (carbonate) into formate that is then used in the same device to operate a direct formate fuel cell (DFFC). The electrochemical reduction of carbonate is carried out on a Sn electrode in a reservoir that maintains a constant carbon balance between carbonate and formate. The electron-rich formate species is converted by the DFFC into electrical energy through electron release. The product of DFFC operation is the electron-deficient carbonate species that diffuses back to the reservoir bulk. It is possible to continuously charge the device using alternative energy (e.g., solar) to convert carbonate to formate for on-demand use in the DFFC; the intermittent nature of alternative energy makes this an attractive design. In this work, we demonstrate a proof-of-concept device that performs reduction of carbonate, storage of formate, and operation of a DFFC.

Improving the Energy Efficiency of Direct Formate Fuel Cells with a Pd/C-CeO2 Anode Catalyst and Anion Exchange Ionomer in the Catalyst Layer

“…Formate salts can be easily stored, transported, and handled in their solid state and can be combined with water to form a liquid fuel solution [2]. Worldwide production of its precursor formic acid is around 7.2 × 10 5 t·y −1 .…”

Bioelectrochemical conversion of CO2 to value added product formate using engineered Methylobacterium extorquens

“…Especially, direct formate fuel cell (DFFC) converting formate to electrical energy is a solution for storing renewable energy because formate can easily store energy generated from various renewable sources such as wind, solar, and hydro. Additionally, formate can be safely transported compared with hydrogen gas because formate is non-flammable, non-toxic and moderately inert in environment 8 , 9 .…”

Highly Selective Electrochemical Conversion of CO2 to HCOOH on Dendritic Indium Foams

“…Among the feedstock chemicals, formic acid is a high‐value commodity chemical,, which is commonly used in various industries, such as tanning industry, textile industry, pharmaceutical industry and rubber processing industry. Additionally, formate can be utilized in direct formic acid fuel cells as a source of renewable energy for electricity production ,. A number of catalysts have been investigated for CO 2 ‐formate conversion.…”

“…Additionally, formate can be utilized in direct formic acid fuel cells as a source of renewable energy for electricity production. [10,11] A number of catalysts have been investigated for CO 2 -formate conversion. A number of catalysts have been investigated for conversion of CO 2 into formate.…”