Conventional lithium‐ion batteries (LIBs) with graphite anodes are approaching their theoretical limitations in energy density. Replacing the conventional graphite anodes with high‐capacity Si‐based anodes represents one of the most promising strategies to greatly boost the energy density of LIBs. However, the inherent huge volume expansion of Si‐based materials after lithiation and the resulting series of intractable problems, such as unstable solid electrolyte interphase layer, cracking of electrode, and especially the rapid capacity degradation of cells, severely restrict the practical application of Si‐based anodes. Over the past decade, numerous reports have demonstrated that polymer binders play a critical role in alleviating the volume expansion and maintaining the integrity and stable cycling of Si‐based anodes. In this review, the state‐of‐the‐art designing of polymer binders for Si‐based anodes have been systematically summarized based on their structures, including the linear, branched, crosslinked, and conjugated conductive polymer binders. Especially, the comprehensive designing of multifunctional polymer binders, by a combination of multiple structures, interactions, crosslinking chemistries, ionic or electronic conductivities, soft and hard segments, and so forth, would be promising to promote the practical application of Si‐based anodes. Finally, a perspective on the rational design of practical polymer binders for the large‐scale application of Si‐based anodes is presented.

Tandem-junction organic solar cells require solar cells with visible light photo-response as front cells, in which an opencircuit voltage (V oc ) above 1.0 V is highly demanded. In this work, we are able to develop electron acceptors to fabricate non-fullerene organic solar cells (NFOSCs) with a very high V oc of 1.14 V. This was realized by designing perylene bisimide (PBI)-based conjugated materials fused with benzodithiophene, in which Cl and S atom were introduced into the molecules in order to lower the frontier energy levels. The fused structures can reduce the aggregation of PBI unit and meanwhile maintain a good charge transport property. The new electron acceptors were applied into NFOSCs by using Cl and S substituted conjugated polymers as electron donor, in which an initial power conversion efficiency of 6.63 % and a high V oc of 1.14 V could be obtained. The results demonstrate that the molecular design by incorporating Cl and S atom into electron acceptors has great potential to realize high performance NFOSCs.found in the Supporting Information. The synthetic procedures were performed under argon atmosphere. Compound 3 aCompound 1 (200.0 mg, 0.21 mmol) and 2 a (399.6 mg, 0.51 mmol) were dissolved in 10 mL toluene. Then, the reaction mixture was flushed with argon for 15 min, and then 23 mg of Pd(PPh 3 ) 4 was added into the solution. The mixture was again flushed with argon for 20 min. The reaction solution was stirred at 115°C for 12 h. After removal of the solvent, the residue was purified by silica gel chromatography (dichloromethane: petroleum ether = 1 : 1) to afford 3 a as a purple product (257 mg, 60 %). 1 H NMR (400 MHz, CDCl 3 ): δ (ppm) 8.68-8.64 (m, 12H), 8.48-8.46 (d, 2H), 8.33 (s, 2H), 7.90 (s, 2H), 5.17 (br, 4H), 2.73-2.72 (d, 4H), 2.24 (br, 8H), 1.86 (br, 8H), 1.63 (br, 2H), 1.27-1.26 (m, 64H), 0.85-0.71 (m, 36H). HRMS (MALDI-TOF) m/z: [M] +