Conversion of Spent Coffee Beans to Electrode Material for Vanadium Redox Flow Batteries

Abstract

This study presents the application of pyrolyzed spent coffee beans as a potential electrode material to replace commercial bipolar graphite plate in vanadium redox flow batteries (VRB). The results indicate that the biochar obtained from spent coffee beans shows relatively good electrochemical charge transfer kinetics of vanadium redox reactions as well as generates higher energy and voltage efficiency in a static cell test when compared to TF6 bipolar graphite plate. Additionally, the biochar was activated via steam at various activation times to increase its surface area, and their effect on the kinetics of the electrochemical reactions was investigated. The activated carbon did not exhibit any improvement neither in electron transfer kinetics nor in the battery efficiency, despite their increased surface area. The performed studies demonstrate that the biochar obtained from spent coffee beans can be a low-cost electrode material for VRB with improved performance characteristics.

Bio‐derived nanomaterials for energy storage and conversion

“…A common method of preparing materials from wood includes pyrolysis, resulting in a biochar with hierarchically structured pores. [ 63,64 ] Further, some notable examples of biomass starting material include coffee, [ 2–4,65 ] aloe vera, [ 66 ] pollen, [ 67 ] phytochemicals, [ 61,62 ] wood, [ 63,64,68,69 ] oatmeal, [ 70 ] bean sprouts, [ 71 ] and bamboo. [ 72,73 ] To summarize, a large number of nanostructures are possible from plant matter, including fibrous materials, [ 8,74 ] sheet‐like structures, [ 72 ] hierarchically porous materials, [ 2–4,63,65,75 ] and spherical particles.…”

“…[ 63,64 ] Further, some notable examples of biomass starting material include coffee, [ 2–4,65 ] aloe vera, [ 66 ] pollen, [ 67 ] phytochemicals, [ 61,62 ] wood, [ 63,64,68,69 ] oatmeal, [ 70 ] bean sprouts, [ 71 ] and bamboo. [ 72,73 ] To summarize, a large number of nanostructures are possible from plant matter, including fibrous materials, [ 8,74 ] sheet‐like structures, [ 72 ] hierarchically porous materials, [ 2–4,63,65,75 ] and spherical particles. [ 61,62 ] In this section, various plant‐based precursors are identified and evaluated based off the type of structures prepared from the plant matter (Table 3).…”

“…Utilization of waste biomass allows for the conversion of waste products, such as coffee grounds, into societally beneficial materials. [ 2–4 ] Both the overwhelming abundance of biomass and the various microstructural properties of biological samples allow for a large selection of biomass to be considered, offering excellent versatility for material design. Unlike viruses or bacteria bio‐template precursors, plants do not multiply as rapidly, therefore self‐assembly methods are not typical of plant derived materials.…”

“…Bioderived nanomaterials have been both directly and indirectly prepared from viruses, bacteria, fungi, protists, plants, and animals. [ 2–4,18,28,35,36,46–49,56,63–73,80–95 ] The different structures, from the many different templates, offer unique features that can benefit the performance of the material synthesized. [ 6 ] Classification of the various applications and the structural features of the materials produced from these sources plays an important role in understanding what types of applications each precursor may lend itself to.…”

Recent Advances in Biochar Modification for Energy Storage in Supercapacitors: A Review

“…Besides all these applications, biochar has attracted much attention in power generation and ESDs such as SCs [21,22]. The electrochemical performance of SCs are mainly dependent on the physical characteristics of electrode materials as electrodes are the main component of SCs.…”