Dopamine-grafted heparin as an additive to the commercialized carboxymethyl cellulose/styrene-butadiene rubber binder for practical use of SiOx/graphite composite anode

Abstract

Graphite is used commercially as the active material in lithium ion batteries, frequently as part of a graphite/SiOx composite. Graphite is used in conjunction with SiOx to overcome the limited energy density of graphite, and to lessen the adverse effects of volume expansion of Si. However, electrodes based on graphite/SiOx composites can be made with only 3–5 wt % SiOx because of the increased failure of electrodes with higher SiOx contents. Here, we developed a new polymer binder, by combining dopamine-grafted heparin with the commercial binder carboxymethyl cellulose (CMC)/styrene butadiene rubber (SBR), in order to more effectively hold the SiOx particles together and prevent disintegration of the electrode during charging and discharging. The crosslinking using acid-base interactions between heparin and CMC and the ion-conducting sulfonate group in heparin, together with the strong adhesion properties of dopamine, yielded better physical properties for the dopamine-heparin-containing CMC/SBR-based electrodes than for the commercial CMC/SBR-based electrodes, and hence yielded excellent cell performance with a retention of 73.5% of the original capacity, a Coulombic efficiency of 99.7% at 150 cycles, and a high capacity of 200 mAh g−1 even at 20 C. Furthermore, a full cell test using the proposed electrode material showed stable cell performance with 89% retention at the 150th cycle.

Silicon‐Based Lithium Ion Battery Systems: State‐of‐the‐Art from Half and Full Cell Viewpoint

“…To maintain the structural stability of SiO x particles and entire electrodes during cycles, Kim and coworkers developed a novel dopamine‐heparin/CMC/SBR binder through a facile crosslinking between CMC, SBR, dopamine, and heparin sulfonate groups ( Figure a). [ 406 ] Benefiting from the high content of functional groups (amine, hydrogen bonding, and sulfonate), the dopamine‐heparin/CMC/SBR binder had high Li + conductivity, strong adhesion strength, and good self‐healing ability. Peeling tests of SiO x /graphite electrodes were carried out to further determine the adhesion of dopamine‐heparin/CMC/SBR.…”

“…Reproduced with permission. [ 406 ] Copyright 2018, Springer Nature. c) Cycling performance of NCM622||SiO x /graphite full cell.…”

Recent Development on Binders for Silicon-Based Anodes in Lithium-Ion Batteries

“…Lee 等 [65] 开发出一种多巴胺功能化肝素/CMC/SBR 的新型聚合物粘合剂, 以更有效地防止 SiO x /石墨复合 电极的崩解. 利用肝素和 CMC 间的酸碱相互作用和肝 素中的离子导电磺酸盐基团, 以及多巴胺的强粘附性, 使得含有多巴胺-肝素/CMC/SBR 基电极的物理性能比 普通的 CMC/SBR 更好, 实现在第 150 次循环时具有 89%保留的稳定电池性能.…”

A conductive self healing polymeric binder using hydrogen bonding for Si anodes in lithium ion batteries

“…Electrodes fabricated from these polymer binders are more effective than the above-mentioned linear type polymer binders. Another approach involves the use of either ionically or electrically conducting polymers to provide ion/electron pathways in the electrodes, respectively [28][29][30][31][32][33][34][35][36][37] . Although some progress has been made as a result of these efforts, none as yet have been able to repair the structural damage in the Si electrode caused by the large volume change of Si.…”