Layering Charged Polymers Enable Highly Integrated High‐Capacity Battery Anodes

Abstract

High-capacity anode materials are promising candidates for increasing the energy density of lithium (Li)-ion batteries due to their high theoretical capacities. However, a rapid capacity fading due to the huge volume changes during charge-discharge cycles limits practical applications. Herein, a layering-charged polymeric binder is introduced that can effectively integrate high-capacity anodes using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. The charged polymeric binder builds a dynamically charge-directed network on the active materials with high versatility and efficiently dissipates the electrode stress with its excellent mechanical properties. In addition, poly(ethylene glycol) (PEG) moieties of the charged binder offer a fast Li-ion conduction pathway that can form an ultra-thick silicon oxide (SiO x )-based electrode (≈10.2 mAh cm −2 ) without compromising the reversible specific capacity and promote effective charge interaction as a mechanical modulator. Such an unprecedented charge-directed binder provides insights into the rational design of a binder for high-capacity anodes.

Constructing Pure Si Anodes for Advanced Lithium Batteries

“…Thus, it is crucial to pay more attention to supplementary materials other than Li host materials (e.g., binder, conductive agent, and electrolyte), which play a distinctive role in promoting the formation of a stable SEI layer and enhancing the structural integrity and conductivity of the electrode. One potential solution is to develop a multifunctional binder that can facilitate the transport of ions while maintaining strong binding with the active material, which enables fabricating the electrodes with high mass loading . For instance, nanoscale Si affords a substantial surface area, which facilitates numerous covalent attachments between native silanol groups on the Si surface and functionalized binder materials .…”

Azacyclic Anchor‐Enabled Cohesive Graphite Electrodes for Sustainable Anion Storage

“…[ 33 ] Most critically, as it relies on weak van der Waals forces, the PVDF binder cannot accommodate the substantial hoop stress generated during electrochemical reactions between anions and graphite, leading to the incapacity to restrain particle crack formation. [ 34 ] Alternatively, commercial hydrophilic binders (e.g., sodium alginate, carboxymethyl cellulose (CMC), and polyacrylic acid (PAA)) have partially succeeded in forming sustainable graphite cathodes. [ 13 ] However, despite their dynamic secondary interactions (i.e., hydrogen bonding or ion–dipole interactions), their linear chain structures cannot withstand substantial amounts of stress, necessitating a strategy for stress delocalization.…”

Modified polyacrylonitrile cross-linked with carboxymethyl cellulose constructing a hydrogen bonding network for high-performance silicon anodes

“…19,30,31 As a novel approach, designing conductive sheaths from the binders on the surface has achieved some remarkable results. 32–34 However, many of these coating materials suffer from the drawback of impeding Li-ion diffusion kinetics and are prone to brittle failure due to their limited ability to withstand severe volume expansion.…”

“…19,30,31 As a novel approach, designing conductive sheaths from the binders on the surface has achieved some remarkable results. [32][33][34] However, many of these coating materials suffer from the drawback of impeding Li-ion diffusion kinetics and are prone to brittle failure due to their limited ability to withstand severe volume expansion. Several conductive polymers, including PPy, 35 PANI, 36 and PEDOT-PSS, 37 have demonstrated promising electrochemical performance when incorporated into Si anodes.…”