Zinc-ion
batteries are promising power sources, but their practical
application is impeded by the Zn dendrite growth and side reactions
at the electrode/electrolyte interface. Here, we report that such
issues can be effectively addressed by a self-healable hydrogel electrolyte.
The electrolyte is comprised of carboxyl-modified poly(vinyl alcohol)
cross-linked by COO–Fe bonding in the presence of Zn(NO3)2 and MnSO4. A quasi-solid-state Zn–MnO2 battery using the electrolyte delivers a specific capacity
up to 177 mAh g–1 after 1000 cycles with a retention
rate of 83%, which is much better than its equivalent using an aqueous
electrolyte. The improvement is attributed to efficient suppression
of the dendrite growth and side reactions at the electrode/electrolyte
by the hydrogel electrolyte. More importantly, the battery autonomously
recovery its energy-storage functions even after multiple physical
damages, showing excellent robustness and reliability. The present
investigation provides an effective strategy to address the energy-storage
performance and reliability of a light-metal battery system.
Poor
stability is a long-standing problem preventing the practical
application of Li metal anodes, which is fundamentally attributed
to their fragile solid electrolyte interphase (SEI) layers that are
intrinsically neither adaptable to the dynamic volume change nor self-healable
after breakage. Here a Li metal anode is effectively stabilized by
in situ integrating its SEI layer into a self-healable polydimethylsiloxane
(PDMS) network cross-linked via imine bonding. The self-healing network
enables the integrated SEI layer to readily accommodate the volume
change but also to repair itself after breaking. Consequently, the
resulting anode exhibits excellent cycling stability and a dendrite-free
morphology. In a Li/LiFePO4 full cell, this strategy leads
to capacity retention up to 99% and a Coulombic efficiency >99.5%
after 300 cycles. Our investigation provides a novel self-healing
strategy for developing stable Li-metal anodes aiming at high energy-density
batteries.
Reliability and safety are critical issues for portable power sources aiming for next-generation electronics. However, most lithium-ion batteries (LIBs) will fail to work or will cause safety problems after physical damage or violent deformation. Here, an omni-healable aqueous LIB, which can self-repair its electrodes and electrolyte simultaneously after mechanical breakage, is fabricated by integrating all of the electroactive components into polymer networks cross-linked by dynamic borate ester bonding. Once suffering from repeated cutoffs, the battery quickly recovers its configuration integrity as well as mechanical and electrochemical properties autonomously without external stimuli. Furthermore, the battery can also be tailored into complicated patterns while maintaining its lithium-storage properties. The present investigation offers a strategy to design a smart and sustainable energy-storage device that has potential applications in wearable/flexible electronics, flexible robot or intelligent apparel, and so on.
Lithium (Li) metal is a promising anode for highenergy-density batteries, but its practical applications are severely hindered by side reactions and dendrite growth at the electrode/ electrolyte interfaces. Herein, we propose that the problems can be effectively solved by introducing an interlayer. The interlayer is composed of a trifluorophenyl-modified poly(ethylene imine) network cross-linked by dynamic imine bonding (PEI-3F). The trifluorophenyl moieties of the interlayer can coordinate with Li + , which enables the interlayer to adjust the distribution of Li + at the electrode/electrolyte interface, while the imine bonding endows the interlayer with self-healing capability. The resulting Li anodes exhibit excellent cycling stability (250 cycles in asymmetric Li||Cu cells) and dendrite-free morphologies. A lithium sulfur (Li-S) cell that uses anodes shows a retention rate of 91% after 100 cycles with a high sulfur loading (5 mg cm −2 ). This study provides a novel strategy to concern the intrinsic drawbacks of a lithium metal anode, which can be extended to other light-metal electrodes aiming for high energy-density batteries.
Shuttling effect and mechanical pulverization are main challenges impeding the practical application of sulfur cathodes for high energy-density Li−S batteries. Here we demonstrate that such issues can be effectively addressed by embedding sulfur microparticles into a self-healable and polysulfide-confining binder comprising of trithiocarbonate, carboxylic acid, and amino functionalities. In the charge/ discharge process, the binder autonomously integrates the pulverized sulfur particles together via its excellent selfhealability and good extendibility, but also effectively confines the generated polysulfides by its polar functionalities. Consequently, the resulting sulfur cathodes deliver high reversible capacity, excellent rate capability, and good cycling stability. This self-healing and confining strategy provides a novel insight into the structural collapse and shuttle effect of sulfur cathodes.
Solid polymer electrolytes (SPEs) are promising for solid-state lithium batteries, but their practical application is significantly impeded by their low ionic conductivity and poor compatibility. Here, we report an ultrahigh elastic SPE based on cross-linked polyurethane (PU), succinonitrile (SN), and lithium bistrifluoromethanesulfonimide (LiTFSI). The resulting electrolyte (PU-SN-LiTFSI) exhibits an ionic conductivity of 2.86 × 10 −4 S cm −1 , a tensile strength of 3.8 MPa, and a breaking elongation exceeding 3000% at room temperature. A solid-state lithium battery using the electrolyte exhibits a high specific capacity of 150 mAh g −1 at 0.2C and a long cycling life of up to 700 cycles at 0.5C at room temperature, showing one of the best performances among its counterparts. The excellent performances are attributed to the fact that its ultrahigh elasticity, good ionic conductivity, tensile strength, and electrochemical stability contribute to robust electrode/ electrolyte interfaces, thus greatly decreasing the charge-transfer resistance in charge/discharge processes. Our investigations provide a novel strategy to address the intrinsic interfacial issue of solid-state batteries.
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