Noncovalent crosslinked liquid metal-incorporated polymer binder based on multiple dynamic bonds for silicon microparticle anode

Silicon (Si) has been deemed as the most promising anode for next-generation lithium-ion batteries due to its high specific capacities. However, the massive volume expansion and contraction during cycling cause severe pulverization of silicon particles and structural collapse of electrodes. Binders play a very critical role in alleviating large stress, while ensuring interparticle adhesion and electrode integration. Herein, we reported a novel multifunctional liquid metal-incorporated (LM) polymer binder for high-capacity silicon anodes by noncovalent assembly of eutectic gallium indium (EGaIn) and polymer matrix. The dynamic crosslinking network with excellent toughness and high mechanical strength is capable of continuously dissipating huge mechanical stress and tolerating the volume change inside the Si particles during repeated cycling. The flowable LM can repair the strain-induced microcracks and maintain the electrically connected integrity of the electrode. As expected, the resultant Si electrode delivers a high initial Coulombic efficiency and a stable cycling performance over 300 cycles at 1 C. Specially, a Si||LiNi0.8Co0.1Mn0.1O2 cell can stably operate for 100 cycles even at a high areal capacity. This conceptual design of liquid metal- incorporated polymer binder offers a new opportunity to promote practical high-capacity anodes for high-energy-dense lithium-ion batteries.