The inferior cycle performance of All-solid-state lithium batteries (ASSLBs) resulting from the low mixed ionic and electronic conductivity in the electrodes, as well as the large interfacial resistance between the electrodes and the electrolyte need to be overcome urgently for commercial applications. Here, an advanced cell construction strategy has been proposed, in which a cohesive and highly conductive poly(oxyethylene) (PEO)-based electrolyte is employed both in the cathode layer and in the interface of the electrolyte/anode, leading to an ASSLB with superior interfacial contact between the electrolyte and the electrodes, and forming a three-dimensional ionic conductive network in the cathode layer. Especially, the NASICON-type ionic conductor covered with the PEO-based polymer, integrating the advantages of an inorganic electrolyte and organic electrolyte, presents an enhanced electrochemical stability and an excellent compatibility with the Li electrode. Consequently, the ASSLBs of LiFePO4 (LFP)/Li with this advanced construction strategy exhibit excellent interfacial compatibility, ultralong cycle life and high capacity, i.e., a reversible discharge capacity maintained at 127.8 mA h g−1 for the 1000th cycle at 1C with a retention of 96.6%, and an initial discharge capacity of 153.4 mA h g−1 with a high retention of 99.9% after 200 cycles at 0.1C. Besides, the high-voltage monopolar stacked batteries with a bipolar structure can be fabricated conveniently, showing an open circuit voltage (OCV) of 6.63 V with a good cycle performance. In particular, the ASSLBs present outstanding safety in terms of nail penetration and burning in fire. Therefore, this advanced cell construction strategy may generate tremendous opportunities in the search for novel emerging solid-state lithium metal batteries.

Safety and the polysulfide shuttle reaction are two major challenges for liquid electrolyte lithium–sulfur (Li–S) batteries. Although use of solid-state electrolytes can overcome these two challenges, it also brings new challenges by increasing the interface resistance and stress/strain. In this work, the interface resistance and stress/strain of sulfur cathodes are significantly reduced by conformal coating ≈2 nm sulfur (S) onto reduced graphene oxide (rGO). An Li–S full cell consisting of an rGO@S-Li10GeP2S12-acetylene black (AB) composite cathode is evaluated. At 60 °C, the all-solid-state Li–S cell demonstrates a similar electrochemical performance as in liquid organic electrolyte, with high rate capacities of 1525.6, 1384.5, 1336.3, 903.2, 502.6, and 204.7 mA h g−1 at 0.05, 0.1, 0.5, 1.0, 2.0, and 5.0 C, respectively. It can maintain a high and reversible capacity of 830 mA h g−1 at 1.0 C for 750 cycles. The uniform distribution of the rGO@S nanocomposite in the Li10GeP2S12-AB matrix generates uniform volume changes during lithiation/delithiation, significantly reducing the stress/strain, thus extending the cycle life. Minimization of the stress/strain of solid cells is the key for a long cycle life of all-solid-state Li–S batteries.

High energy and power densities are the greatest challenge for all-solid-state lithium batteries due to the poor interfacial compatibility between electrodes and electrolytes as well as low lithium ion transfer kinetics in solid materials. Intimate contact at the cathode–solid electrolyte interface and high ionic conductivity of solid electrolyte are crucial to realizing high-performance all-solid-state lithium batteries. Here, we report a general interfacial architecture, i.e., Li7P3S11 electrolyte particles anchored on cobalt sulfide nanosheets, by an in situ liquid-phase approach. The anchored Li7P3S11 electrolyte particle size is around 10 nm, which is the smallest sulfide electrolyte particles reported to date, leading to an increased contact area and intimate contact interface between electrolyte and active materials. The neat Li7P3S11 electrolyte synthesized by the same liquid-phase approach exhibits a very high ionic conductivity of 1.5 × 10–3 S cm–1 with a particle size of 0.4–1.0 μm. All-solid-state lithium batteries employing cobalt sulfide–Li7P3S11 nanocomposites in combination with the neat Li7P3S11 electrolyte and Super P as the cathode and lithium metal as the anode exhibit excellent rate capability and cycling stability, showing reversible discharge capacity of 421 mAh g–1 at 1.27 mA cm–2 after 1000 cycles. Moreover, the obtained all-solid-state lithium batteries possesses very high energy and power densities, exhibiting 360 Wh kg–1 and 3823 W kg–1 at current densities of 0.13 and 12.73 mA cm–2, respectively. This contribution demonstrates a new interfacial design for all-solid-state battery with high performance.Keywords: All-solid-state lithium battery; cobalt sulfide−Li7P3S11 nanocomposites; cycling stability; interfacial architecture; sulfide electrolyte;

•Li10GeP2S12 was selected to disperse into PEO-based polymer to prepare a new SPE.•The ionic conductivity and electrochemical stability of new SPE electrolyte is improved.•The electrochemical window of new SPE is broadened.•The LiFePO4/Li battery fabricated with this new SPE exhibited excellent performance.Li10GeP2S12 (LGPS) is incorporated into polyethylene oxide (PEO) matrix to fabricate composite solid polymer electrolyte (SPE) membranes. The lithium ion conductivities of as-prepared composite membranes are evaluated, and the optimal composite membrane exhibits a maximum ionic conductivity of 1.21 × 10−3 S cm−1 at 80 °C and an electrochemical window of 0–5.7 V. The phase transition behaviors for electrolytes are characterized by DSC, and the possible reasons for their enhanced ionic conductivities are discussed. The LGPS microparticles, acting as active fillers incorporation into the PEO matrix, have a positive effect on the ionic conductivity, lithium ion transference number and electrochemical stabilities. In addition, two kinds of all-solid-state lithium batteries (LiFeO4/SPE/Li and LiCoO2/SPE/Li) are fabricated to demonstrate the good compatibility between this new SPE membrane and different electrodes. And the LiFePO4/Li battery exhibits fascinating electrochemical performance with high capacity retention (92.5% after 50 cycles at 60 °C) and attractive capacities of 158, 148, 138 and 99 mAh g−1 at current rates of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C, respectively. It is demonstrated that this new composite SPE should be a promising electrolyte applied in solid state batteries based on lithium metal electrode.

•Fundamental lithium storage behavior of solid-state battery with NCA is investigated.•The relationship between electrochemical performances and structure is revealed.•Particle size, surface impurities and defects affect the interfacial resistance.•A ball-milling followed by post-annealing is demonstrated to improve performances.•The NCA in NCA/Li10GeP2S12/Li-In cell exhibits a discharge capacity of 146 mAh g−1.An insightful study on the fundamental lithium storage behavior of all-solid-state lithium battery with a structure of LiNi0.8Co0.15Al0.05O2 (NCA)/Li10GeP2S12/Li-In is carried out in this work. The relationship between electrochemical performances and particle size, surface impurities and defects of the NCA positive material is systematically investigated. It is found that a ball-milling technique can decrease the particle size and remove surface impurities of the NCA cathode while also give rise to surface defects which could be recovered by a post-annealing process. The results indicate that the interfacial resistance between the NCA and Li10GeP2S12 is obviously decreased during the ball-milling followed by a post-annealing. Consequently, the discharge capacity of NCA in the NCA/Li10GeP2S12/Li-In solid-state battery is significantly enhanced, which exhibits a discharge capacity of 146 mAh g−1 at 25 °C.

•A promising PEO/LAGP hybrid electrolyte prepared by a simple method which can be manufactured easily in industry scale.•The electrolyte exhibits an ionic conductivity of 6.76 × 10− 4 S cm− 1 and an electrochemical window of 0-5.3 V at 60 °C.•The hybrid electrolyte has improved electrochemical and mechanical properties.•All-solid-state battery exhibits high capacity retention and attractive capacities.Four types of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) with different particle sizes are selected as active fillers incorporated into polyethylene oxide (PEO) matrix to fabricate PEO/LAGP hybrid electrolytes at drying room. The results show that LAGP particles have a positive effect on the ionic conductivity, lithium ion transference number, electrochemical stabilities and mechanical properties. Among the PEO/LAGP hybrid electrolytes, the PEO-20%LAGP-I hybrid electrolyte exhibits a maximum ionic conductivity of 6.76 × 10− 4 S cm− 1 and an electrochemical window of 0–5.3 V at 60 °C. The possible reasons for conductivities improving are discussed through characterizing the phase transition behaviors of electrolytes. All-solid-state battery LiFePO4/Li is fabricated and presents fascinating electrochemical performance with high capacity retention (close to 90% after 50 cycles at 60 °C) and attractive capacities of 166, 155, 143 and 108 mAh g− 1 at current rates of 0.1, 0.2, 0.5 and 1 C, respectively. This work provides a promising PEO/LAGP hybrid electrolyte prepared by a simple method which can be manufactured easily in industry scale.

•The conductivity of 70Li2S·30P2S5 is enhanced by Li3PO4 substitution for P2S5.•The cell's discharge capacity is improved by Li3PO4 substitution in 70Li2S·30P2S5.•The presence of O could reduce the impedance of the electrode-electrolyte interface.70Li2S·(30-x)P2S5·xLi3PO4 (mol%) amorphous powders are prepared by a high-energy ball milling technique, and the glass-ceramics are obtained by the crystallization of as-prepared amorphous samples. The XRD patterns show that a crystalline phase with a Li7P3S11 structure is obtained for x ≤ 3, while a structure change is observed for x = 5. The Li+-ion conductivity is enhanced by the substitution of Li3PO4 for P2S5, and the 70Li2S·29P2S5·1Li3PO4 glass-ceramics exhibit the highest total conductivity of 1.87 × 10−3 S cm−1 at 25 °C and the lowest activation energy of 18 kJ mol−1. The LiCoO2 in the all-solid-state cell of In-Li/70Li2S·29P2S5·1Li3PO4/LiCoO2 exhibits a discharge capacity of 108 mAh g−1, which is 20% higher than that in the In-Li/70Li2S·30P2S5/LiCoO2 cell. The higher discharge capacity of the LiCoO2 electrode is attributed to the higher Li+-ion conductivity of the solid electrolyte and lower interface resistance of electrode–electrolyte.

MoS2 nanoflowers consisting of nanosheets are synthesized by a one-step hydrothermal method. The interlayer distances of the MoS2 nanosheets, accompanied with the changes of crystallinity, defects, specific surface areas as well as the thickness of the MoS2 nanosheets, can be well controlled via simply altering hydrothermal reaction temperatures. The effect of interlayer distances on the lithium storage capability for lithium ion batteries is investigated. The results show that MoS2 synthesized under 200 °C with an interlayer distance of 0.65 nm exhibit the highest lithium storage capacity and the best rate capability, showing a high discharge capacity of 814.2 mA h g−1 at 100 mA g−1 after 50 cycles and as high as 652.2 mA h g−1 and 547.3 mA h g−1 at current densities of 1 A g−1 and 2 A g−1 at 25 °C, respectively. The excellent lithium storage properties of the resultant MoS2 nanoflowers are attributed to its controllable optimized interplanar distance with good crystallinity, appropriate surface area and defects as well as thickness of the nanosheets.

•The synthesized Li10GeP2S12 shows higher ionic conductivity than Li3.25Ge0.25P0.75S4.•All-solid-state lithium batteries containing NCA cathode and LGPS were demonstrated.•NCA/Li10GeP2S12/Li-In battery shows superior electrochemical performances.•Li10GeP2S12 exhibits low interfacial resistance with NCA cathode materials.The effect of solid electrolytes, i.e. Li10GeP2S12 and Li3.25Ge0.25P0.75S4, on the rate and low temperature performances of LiNi0.8Co0.15Al0.05O2 (NCA) cathode in all solid state lithium batteries is investigated. The ionic conductivities for the synthesized Li10GeP2S12 and Li3.25Ge0.25P0.75S4 at room temperature (RT) are 8.27 × 10− 3 and 2.03 × 10− 3 S cm− 1, respectively. These solid electrolytes are demonstrated as electrolytes for all solid state lithium batteries containing NCA cathode for the first time. The results show that Li10GeP2S12 based battery exhibits superior rate performance (72.3 mAh g− 1 at 1 C, RT), cycling stability (capacity retention of 87.1% after 30 cycles at 0.1 C, RT) and low temperature performance (79.2 mAh g− 1 at 0.1 C and − 10 °C), which can be ascribed to its higher ionic conductivity and lower interfacial resistance between Li10GeP2S12 and NCA cathode. It is indicated that all solid state lithium batteries with NCA cathode and Li10GeP2S12 solid electrolyte can realize its potential application in high power and low temperature conditions.

LiNi1/3Co1/3Mn1/3O2 cathodes have been prepared by a solid-state reaction process. The effects of calcination and post-annealing temperature on electrochemical performances were systematically investigated for both of the lithium-ion batteries with liquid electrolytes and all-solid-state lithium batteries with sulfide solid electrolytes. The particle size of the LiNi1/3Co1/3Mn1/3O2 materials increases with calcination temperatures, whereas after calcination, the shape and size of LiNi1/3Co1/3Mn1/3O2 particles were independent of post-annealing temperatures. The LiNi1/3Co1/3Mn1/3O2 calcinated at 850 °C and followed by post-annealing at 800 °C maintains 97.6 % capacity retention after 30 cycles and has a capacity of 117 mAh g−1 at a current of 5 C (current density of 24.1 mA/cm2) in a voltage range of 2.8 and 4.3 V in lithium-ion batteries. Moreover, the optimal sample has the first discharge capacity of about 115 mAh g−1 at a current density of 0.11 mA cm−2 in the all-solid-state lithium battery with Li10GeP2S12 as solid state electrolyte. Electrochemical impedance spectroscopy measurements show that the post-annealing process plays an important role in suppressing the increase of cell impedance during charging–discharging. The experimental results suggest that the post-annealed LiNi1/3Co1/3Mn1/3O2 material is very suitable as one of the leading cathode materials for lithium-ion and solid-state lithium batteries with long cycle life and high power density.

The nanostructured Si/graphite composites embedded with the pyrolyzed polyethylene glycol was synthesized from coarse silicon and natural graphite by a facile and cost-effective approach. The Si/C nanocomposite showed the fluffy carbon-coated structure, which was confirmed by the SEM and TEM measurements. The as-obtained Si/C nanocomposite, employed as anode material in lithium-ion batteries, exhibited significantly enhanced rate capability and cycling stability. The improved electrochemical stability of the composite was evaluated by EIS and galvanostatically charge/discharge test. A reversible capacities as high as 85% and 91% of the initial charge capacities, could be maintained for the Si/C nanocomposite electrode after 40 cycles under the high current densities of 500 and 1,000 mA g−1, respectively. The relatively low cost and excellent electrochemical capability of the Si/C nanocomposite would well meet the challenge in rapid charge and discharge for large-size lithium-ion rechargeable batteries.

The porous hematite (α-Fe2O3) nanorods, having diameters of 30–60 nm, were prepared through thermal decomposition of FeC2O4·2H2O nanorods that were readily synthesized through poly(vinyl alcohol)-assisted precipitation process. Compared to the commercial α-Fe2O3 powders in submicrometer sizes, the porous α-Fe2O3 nanorods, as an electrode material in lithium-ion batteries, exhibited significantly enhanced rate capability due to their nanorod shape and porous structure. When discharging at 0.1C (1C = 1005 mA/g) and charging at different rates (0.1C, 0.5C, and 1C), the porous α-Fe2O3 nanorods could deliver a capacity of over than 1130 mAh/g; while cycling at 1C rate, the nanorods could maintain a discharge capacity as high as 916 mAh/g after 100 cycles.Highlights► The porous hematite nanorods are prepared by decomposition of FeC2O4•2H2O nanorods. ► The synthesis method shows us a facile, low-cost and highly productive strategy. ► The porous hematite nanorods are suitable for a promising anode material in LIBs. ► Significantly enhanced rate capability is achieved. ► The porous hematite nanorods also show high capacity and good cycling stability.

A graphene-based nanocomposite Cu2ZnSnS4/graphene (CZTS/graphene) is employed as a promising active material for all-solid-state lithium batteries for the first time. Meantime, lithium metal is used as an anode in order to maximize the energy density of the batteries with the sulfide electrolytes. The solid electrolyte bilayer, i.e. Li10GeP2S12 and 70% Li2S–29% P2S5–1% P2O5, is designed, where 70% Li2S–29% P2S5–1% P2O5 is used as the interface with lithium metal for the purpose of avoiding the reduction reaction with Li10GeP2S12. CZTS/graphene nanocomposites, with the CZTS nanoparticles uniformly anchored on the graphene nanosheets, are prepared by a simple hydrothermal reaction. The unique structure endows significantly reduced lithium ion diffusion lengths in CZTS nanoparticles as well as intimate contact between CZTS nanoparticles and sulfide electrolytes, leading to favorable lithium ionic and electronic conduction pathways. The results reveal that the CZTS/graphene-21 in all-solid-state lithium batteries shows the discharge capacity of 645.4 mA h g−1 after 50 cycles at 50 mA g−1, corresponding to a very high energy density of 346.2 W h kg−1. Even at high current densities of 100 and 1000 mA g−1, the CZTS/graphene-21 can still deliver the discharge specific capacities as high as 544.6 and 233.9 mA h g−1 after 100 and 300 cycles, respectively.A graphene-based Cu2ZnSnS4 nanocomposite is demonstrated as a promising active material for all-solid-state lithium batteries, which shows good interfacial compatibility with sulfide electrolyte, resulting excellent rate capability and cycling stability. Meanwhile, lithium metal anode is employed in order to maximize the energy density of the all-solid-state lithium batteries, showing a high energy density of 346.2 W h kg−1 at 50 mA g−1.Download high-res image (268KB)Download full-size image