No abstract

Despite their potential as post lithium‐ion batteries, solid‐state Li‐metal batteries are struggling with insufficient electrochemical sustainability and ambient operation limitations. These challenges mainly stem from lack of reliable solid‐state electrolytes. Here, a new class of single‐ion conducting quasi‐solid‐state soft electrolyte (SICSE) for practical semi‐solid Li‐metal batteries (SSLMBs) is demonstrated. The SICSE consists of an ion‐rectifying compliant skeleton and a nonflammable coordinated electrolyte. Rheology‐tuned SICSE pastes, in combination with UV curing‐assisted multistage printing, allow fabrication of seamlessly integrated SSLMBs (composed of a Li metal anode and LiNi0.8Co0.1Mn0.1 cathode) without undergoing high‐pressure/high‐temperature manufacturing steps. The single‐ion conducting capability of the SICSE plays a viable role in stabilizing the interfaces with the electrodes. The resulting SSLMB full cell exhibits stable cycling performance and bipolar configurations with tunable voltages and high gravimetric/volumetric energy densities (476 Wh kgcell−1/1102 Wh Lcell−1 at four‐stacked cells with 16.656 V) under ambient operating conditions, along with low‐temperature performance, mechanical foldability, and nonflammability.

high-voltage requirements. [1][2][3][4] However, the advancements of cathode active materials are overshadowed by the slow development of cathode binders, which should not be underestimated in terms of enabling practical cathode sheets. This issue becomes more stringent for the development of high-mass-loading cathode sheets, which have garnered considerable attention as a facile and scalable way to construct high-energy-density Li-ion batteries. [5][6][7] Major challenges facing the high-massloading cathode sheets include nonuniform electron/ion conduction networks in their through-thickness direction, [8][9][10][11][12] insufficient adhesion (between electrode active layers and current collectors) under electrolyte-soaked states, [13][14][15] and dissolution of transition metal (TM) ions from cathode active materials. [8,16,17] Notably, these challenges are closely dependent on cathode binders. Several previous studies on cathode binders have focused on the synthesis and engineering of new materials, with particular attention to replacing polyvinylidene fluoride (PVdF) binders that have been predominantly used in commercial cathodes. For example, gum materials [18,19] such as xanthan and guar gums with hydroxyl groups enhance the structural stability and electrochemical performance of overlithiated layered oxide (OLO) cathodes by chelating the dissolved TM ions. Carboxymethyl cellulose (CMC) exerted a strong binding force on OLO and mitigated the phase transition of OLO during cycling. [20,21] Owing to its hydroxyl groups, lignin enhanced the adhesion between LiNi 0.5 Mn 1.5 O 4 (LNMO) active materials and current collectors, and contributed to the formation of uniform cathode-electrolyte interphase (CEI). [22] In addition to these biomaterials, polyacrylic acid (PAA) [23] and Li-PAA [24] were explored as binders for the OLO and LNMO cathodes, which formed stable CEI layers and suppressed the dissolution of TM ions.However, these cathode binders were only suitable for aqueous slurry-based cathode fabrication processes due to their hydrophilic functional groups. More notably, these aqueous binders were not suitable for moisture-sensitive Ni-rich cathode active materials, which have gained considerable attention for high-energy-density Li-batteries used in long-range electric vehicles. The Ni-rich cathode active materials often undergo structural disruption when exposed to water molecules, [25] thus generating unwanted residual Li compounds such as LiOH and In contrast to noteworthy advancements in cathode active materials for lithium-ion batteries, the development of cathode binders has been relatively slow. This issue is more serious for high-mass-loading cathodes, which are preferentially used as a facile approach to enable high-energy-density Li-ion batteries. Here, amphiphilic bottlebrush polymers (BBPs) are designed as a new class of cathode binder material. Using poly (acrylic acid) (PAA) as a sidechain, BBPs are synthesized through ring-opening metathesis polymerization. The BBPs are amphiphilic in nature...

Herein, we report a charge-transfer complex electrolyte additive, 7,7,8,8-tetracyanoquinodimethane (TCNQ), with high Zn affinity, which was tightly adsorbed on the surface of a Zn anode to form a dense and robust interfacial complex layer and suppress the activity of H2O. As verified by comprehensive experimental and computational analyses, this complex layer could construct a Zn–Zn(TCNQ)2 Ohmic contact interface, guide rapid ion/electron transport, ameliorate electric field distribution, and inhibit the direct contact between the active H2O and Zn anode, demonstrating a dendrite-free Zn anode and facile Zn plating/stripping kinetics. Consequently, the Zn||Zn symmetrical cell exhibits a high Zn plating/stripping reversibility of over 1000 h at 20 mA cm–2 and 5 mA h cm–2 and a high depth of discharge (43%). Moreover, the Zn||MnO2 full cell delivers a high capacity of 143.3 mA h g–1 at 2000 mA g–1 even after 4000 cycles and a capacity retention of 94.7% after returning to 100 mA g–1.

Lithium metal batteries have higher theoretical energy than their Li-ion counterparts, where graphite is used at the anode. However, one of the main stumbling blocks in developing practical Li metal batteries is the lack of cathodes with high-mass-loading capable of delivering highly reversible redox reactions. To overcome this issue, here we report an electrode structure that incorporates a UV-cured non-aqueous gel electrolyte and a cathode where the LiNi0.8Co0.1Mn0.1O2 active material is contained in an electron-conductive matrix produced via simultaneous electrospinning and electrospraying. This peculiar structure prevents the solvent-drying-triggered non-uniform distribution of electrode components and shortens the time for cell aging while improving the overall redox homogeneity. Moreover, the electron-conductive matrix eliminates the use of the metal current collector. When a cathode with a mass loading of 60 mg cm−2 is coupled with a 100 µm thick Li metal electrode using additional non-aqueous fluorinated electrolyte solution in lab-scale pouch cell configuration, a specific energy and energy density of 321 Wh kg−1 and 772 Wh L−1 (based on the total mass of the cell), respectively, can be delivered in the initial cycle at 0.1 C (i.e., 1.2 mA cm−2) and 25 °C.