TY - JOUR
T1 - Electrolyte ions-matching hierarchically porous biochar electrodes with an extended potential window for next-generation supercapacitors
AU - Rama Raju, Ganji Seeta
AU - Kondrat, Svyatoslav
AU - Chodankar, Nilesh R.
AU - Hwang, Seung Kyu
AU - Lee, Jeong Han
AU - Long, Teng
AU - Pavitra, Eluri
AU - Patil, Swati J.
AU - Ranjith, Kugalur Shanmugam
AU - Rao, M. V.Basaveswara
AU - Wu, Peng
AU - Roh, Kwang Chul
AU - Huh, Yun Suk
AU - Han, Young Kyu
N1 - Publisher Copyright:
© 2023 The Royal Society of Chemistry
PY - 2023/6/1
Y1 - 2023/6/1
N2 - Engineering high-performance carbonaceous electrode materials from earth-abundant biomass has attracted substantial attention for its applicability in next-generation supercapacitors (SCs). However, these materials exhibit low specific energy due to the dominance of mesopores and a limited potential window. To overcome these shortcomings, herein, we synthesize Miscanthus sinensis (silver grass)-derived hierarchically-porous activated carbons (SHACs) via pyrolysis, carbonization, and KOH activation. We test the SHAC electrodes with different electrolytes, showing how an electrolyte-electrode pair can be tuned to boost energy and power densities. Owing to the synergetic effect of the size-balanced proportion of micropores matched with the size of electrolyte ions, in KOH electrolyte, the SHAC electrode produces a high specific capacitance (592 F g−1) while, simultaneously, providing faster charging compared to Na2SO4 electrolyte. We rationalize these findings with molecular dynamics simulations, demonstrating the avoidance of power-density trade-off, typical for microporous SCs. Upon adding K3Fe(CN)6 redox species to KOH electrolyte (hybrid electrolyte), capacitance increases 2.53 fold (380 to 963 F g−1 at 5 A g−1) due to the synergy of capacitive and faradaic energy storage mechanisms. In the hybrid electrolyte, a SHAC electrode-embedded symmetric SC (SSC) offers a high cycling stability (97%) with 1.6 V wide operational voltage and permits energy storage and power density higher than those reported so far for aqueous electrolyte-based SSCs and asymmetric SCs. In addition, these SSCs provide long-lasting operational capabilities that are useful for driving various portable electronic devices. The obtained results demonstrate a feasible methodology to utilize the maximum available surface area of carbonaceous materials for electrochemical energy storage applications.
AB - Engineering high-performance carbonaceous electrode materials from earth-abundant biomass has attracted substantial attention for its applicability in next-generation supercapacitors (SCs). However, these materials exhibit low specific energy due to the dominance of mesopores and a limited potential window. To overcome these shortcomings, herein, we synthesize Miscanthus sinensis (silver grass)-derived hierarchically-porous activated carbons (SHACs) via pyrolysis, carbonization, and KOH activation. We test the SHAC electrodes with different electrolytes, showing how an electrolyte-electrode pair can be tuned to boost energy and power densities. Owing to the synergetic effect of the size-balanced proportion of micropores matched with the size of electrolyte ions, in KOH electrolyte, the SHAC electrode produces a high specific capacitance (592 F g−1) while, simultaneously, providing faster charging compared to Na2SO4 electrolyte. We rationalize these findings with molecular dynamics simulations, demonstrating the avoidance of power-density trade-off, typical for microporous SCs. Upon adding K3Fe(CN)6 redox species to KOH electrolyte (hybrid electrolyte), capacitance increases 2.53 fold (380 to 963 F g−1 at 5 A g−1) due to the synergy of capacitive and faradaic energy storage mechanisms. In the hybrid electrolyte, a SHAC electrode-embedded symmetric SC (SSC) offers a high cycling stability (97%) with 1.6 V wide operational voltage and permits energy storage and power density higher than those reported so far for aqueous electrolyte-based SSCs and asymmetric SCs. In addition, these SSCs provide long-lasting operational capabilities that are useful for driving various portable electronic devices. The obtained results demonstrate a feasible methodology to utilize the maximum available surface area of carbonaceous materials for electrochemical energy storage applications.
UR - http://www.scopus.com/inward/record.url?scp=85165274126&partnerID=8YFLogxK
U2 - 10.1039/d3ta01829f
DO - 10.1039/d3ta01829f
M3 - Article
AN - SCOPUS:85165274126
SN - 2050-7488
VL - 11
SP - 15540
EP - 15552
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 28
ER -