TY - JOUR
T1 - Removing electrochemical constraints on polytetrafluoroethylene as dry-process binder for high-loading graphite anodes
AU - Wei, Ziqi
AU - Kong, Dewen
AU - Quan, Lijiao
AU - He, Jiarong
AU - Liu, Jingyuan
AU - Tang, Ziyuan
AU - Chen, Si
AU - Cai, Qinqin
AU - Zhang, Ruiqin
AU - Liu, Haijing
AU - Xu, Kang
AU - Xing, Lidan
AU - Li, Weishan
PY - 2024/5/15
Y1 - 2024/5/15
N2 - The environmentally friendly polytetrafluoroethylene (PTFE) binder, known for its strong bonding, is ideal for high-loading electrode preparation in solvent-free dry processes. However, its use in graphite anodes is hindered by a tendency to undergo reduction at low potentials, causing substantial capacity loss. Herein, we identified an irreversible reductive of PTFE at ∼1.2 V vs. Li/Li+, involving partial substitution of F atoms with H in its carbon chain and subsequent LiF formation. Using this insight, we developed a polyethylene oxide coating to prevent electrical contact between graphite and PTFE binder, successfully inhibiting PTFE reduction. This coating facilitated the effective use of PTFE in high-loading lithium-ion battery (LIB) pouch cells (4.8 mAh/cm2 LiNi0.75Mn0.25O2 and 5.2 mAh/cm2 graphite) via dry-process fabrication, achieving an energy density of 258.7 Wh/kg and reducing initial irreversible decompositions from 52.91% to 16.34%. The cost-effective PTFE, coupled with solvent-free, high-loading electrode fabrication, offers an economical and green approach to large-scale electrification. © 2024 Elsevier Inc.
AB - The environmentally friendly polytetrafluoroethylene (PTFE) binder, known for its strong bonding, is ideal for high-loading electrode preparation in solvent-free dry processes. However, its use in graphite anodes is hindered by a tendency to undergo reduction at low potentials, causing substantial capacity loss. Herein, we identified an irreversible reductive of PTFE at ∼1.2 V vs. Li/Li+, involving partial substitution of F atoms with H in its carbon chain and subsequent LiF formation. Using this insight, we developed a polyethylene oxide coating to prevent electrical contact between graphite and PTFE binder, successfully inhibiting PTFE reduction. This coating facilitated the effective use of PTFE in high-loading lithium-ion battery (LIB) pouch cells (4.8 mAh/cm2 LiNi0.75Mn0.25O2 and 5.2 mAh/cm2 graphite) via dry-process fabrication, achieving an energy density of 258.7 Wh/kg and reducing initial irreversible decompositions from 52.91% to 16.34%. The cost-effective PTFE, coupled with solvent-free, high-loading electrode fabrication, offers an economical and green approach to large-scale electrification. © 2024 Elsevier Inc.
KW - lithium-ion batteries
KW - solvent-free dry-process fabrication
KW - PTFE binder
KW - high-loading graphite electrode
UR - http://www.scopus.com/inward/record.url?scp=85187682730&partnerID=8YFLogxK
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-85187682730&origin=recordpage
U2 - 10.1016/j.joule.2024.01.028
DO - 10.1016/j.joule.2024.01.028
M3 - RGC 21 - Publication in refereed journal
SN - 2542-4351
VL - 8
SP - 1350
EP - 1363
JO - Joule
JF - Joule
IS - 5
ER -
