High-Mass-Loading Anode-Free Lithium–Sulfur Batteries Enabled by a Binary Binder with Fast Lithium-Ion Transport

To realize the practical viability of lithium–sulfur batteries (LSBs), it is crucial to develop advanced electrode materials that enable high-mass-loading cells with limited lithium and a lean electrolyte. We present here the design of a binary binder by combining poly(ethylene oxide) (PEO) with a cross-linked quadripolymer, which exhibits high mechanical strength and electrochemical stability. The tightly interwoven binder network enhances the structural reliability of PEO in ether-based electrolytes and the resilience of the electrode to accommodate volume changes during cycling. Moreover, the anode–electrolyte interfacial chemistry and the sulfur redox kinetics are ameliorated by this binder due to its strong polysulfide adsorbability and the multiple lithium-ion transport channels in the PEO matrix and quadripolymer skeleton. With this binder, anode-free full cells with a Li2S loading of 5.4 mg cm–2 and a low electrolyte/sulfur ratio of 7 μL mg–1 display a significantly improved capacity retention of 79% after 100 cycles.