Exploring
high performance solid electrolytes is essential for
the practical application of solid-state lithium–metal batteries.
Here, graphene oxide (GO) is employed to improve the electrochemical
performance, thermal stability, and mechanical strength of the poly(ethylene
oxide) (PEO) based electrolyte. The ionic conductivity of the hybrid
electrolyte containing 1 wt % GO reaches 1.54 × 10–5 S cm–1 at 24 °C, which is 7 times that of
the electrolyte without GO, and the activation energy decreases from
1.01 to 0.64 eV. It is found that GO can suppress the formation of
crystalline nuclei of PEO, thus increase the amorphous regions, and
improve the movement ability of the PEO segments. Importantly, GO-modified
PEO electrolyte not only has a wide electrochemical window (∼5
V) but also increases the lithium ion migration number to 0.42. Taking
advantage of the decent GO–PEO solid electrolyte, the symmetric
Li/Li cell can stably cycle for 600 h with a very small overpotential
(27 mV) at 0.1 mA cm–2, showing excellent performance
in inhibiting lithium dendrites. Most importantly, the LiFePO4//GO–PEO//Li full battery also delivers superior cycle
and rate properties, with an initial discharge capacity of 142 mAh
g–1 at 0.5 C and 91% capacity retention after 100
cycles. Moreover, the full battery can stably cycle for more than
450 charge–discharge cycles at 1 C. It is anticipated that
PEO polymer electrolyte modified by GO has great practical application
potential.
Direct application of metallic lithium (Li) as the anode in rechargeable lithium metal batteries (LMBs) is still hindered by some annoying issues such as lithium dendrites formation, low Coulombic efficiency, and safety concerns arising therefrom. Herein, an advanced composite separator is prepared by facilely blade coating lightweight and thin functional layers on commercial 12 μm polyethylene separator to stabilize the Li anode. The composite separator simultaneously improves the Li ion transport and lithium deposition behaviors with uniform lithium ion distribution properties, enabling the dendrite-free Li deposition. As a result, the lithium anode can stably cycle up to 3000 cycles with the high capacity of 3.5 mAh cm −2 . Moreover, the composite separator exhibits wide compatibility in LMBs (Li-S and Li-ion battery) and delivers stable cycling performance and high Coulombic efficiency both in coin and lab-level soft-pack cells. Thus, this cost-effective modification strategy exhibits great application potential in high-energy LMBs.
Hybrid
polymer electrolytes with excellent performance at high temperatures
are very promising for developing solid-state lithium batteries for
high-temperature applications. Herein, we use a self-supporting hydroxyapatite
(HAP) nanowire membrane as a filler to improve the performance of
a poly(ethylene oxide) (PEO)-based solid-state electrolyte. The HAP
membrane could comprehensively improve the properties of the hybrid
polymer electrolyte, including the higher room-temperature ionic conductivity
of 1.05 × 10–5 S cm–1, broad
electrochemical windows of up to 5.9 V at 60 °C and 4.9 V at
160 °C, and a high lithium-ion migration of 0.69. In addition,
the LiFePO4//Li full battery with a solid electrolyte possesses
good rate capability, cycling, and Coulomb efficiency at extreme high
temperatures, that is, after 300 continuous charge and discharge cycles
at 4 C rate, the discharge capacity retention rate is 77% and the
Coulomb efficiency is 99%. The use of the flexible self-supporting
HAP nanowire membrane to improve the PEO-based solid composite electrolyte
provides new strategies and opportunities for developing rechargeable
lithium batteries in extreme high-temperature applications.
electrocatalyst exhibits a high capacity of 695.2 mA h g −1 . An energy density of 838.6 Wh kg Zn −1 and an outstanding stability of 184 h at 10 mA cm −2 are demonstrated.
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