Fig. 1

Schematic illustration of porous electrodes"

Fig. 2

(a) Powder microelectrodes[29]; (b) Quasi-random assembled single particle electrode[33]"

Fig. 3

Schematic of the diffusion field near the ultramicroelectrode[59]"

Fig. 4

Two configurations for SECCM[73] (a) Double-barrel pipettes; (b) Single-barrel pipette"

Fig. 5

Dc and ac ion conductance current during double-barrel pipettes approaching the substrate[75]"

Fig. 6

Surface morphology and corresponding SEM images of composite electrodes and secondary particles obtained by SECCM[64]"

Fig. 7

(a) CV curves of LMO single particles and SEM image of particles[63]; (b) Current response and diffusion coefficient distribution of LTO thin film electrode at the constant potential[67]; (c) CV curves of LFP particles and conductive agent on the surface of composite electrode[65]; (d) Local CV curves of ZrO2-coated LCO electrode[70]"

Fig. 8

(a) Surface morphology and current response of LFP composite electrode[65]; (b) Galvanostatic charging and discharging curves of a LFP single secondary particle[65]; Galvanostatic charging and discharging curves of (c) LFP single particles and (d) coin cell[68]; (e) Galvanostatic charging and discharging curves of a LMO nanoscale single particle[63]"

Fig. 9

(a) SEM image of nitrogen-doped reduced graphene oxide (N-rGO)/indium tin oxide (ITO) electrode surface[61]; (b) Double-layer capacitance distribution on the sample surface[61]; (c) Charge transfer resistance distribution on the sample surface[61]; Tafel curves, exchange current density, and charge transfer resistance in organic electrolyte (d) and aqueous electrolyte (e) [62]; (f) Schematic of the de-solvation process in organic and aqueous electrolyte[62]"

Fig. 10

Schematic of the experimental setup of the conventional contact-based single-particle microelectrode designed by Uchida et al[77]"

Fig. 11

Usage frequency of electrolytes and solvents in literature for contact-based single-particle microelectrodes"

Fig. 12

(a) A microreactor with a integrated single-particle microelectrode operating in a FIB/SEM chamber[101]; (b) Evolution of the microstructure of an NCA single particle during cycling[101]; (c) Schematic of a microreactor used for in-situ observation of particle microstructure evolution and volume changes[102]; (d) SEM image of a tin single-particle microelectrode[102]"

Fig. 13

(a) The fabrication process of integrated single-particle microelectrodes[106]; (b) Electrochemical testing system of a LTO single-particle microelectrode[108]; (c) Rate performance of LTO single-particle microelectrodes at different temperatures[108]; (d) Capacity retention of LTO single-particle microelectrodes during cycling[108]; (e) Electrochemical testing system of a SiO x single-particle microelectrode[111]"

Fig. 14

(a) Schematic of the reaction chamber with a integrated single-particle microelectrode[112]; (b) SEM and optical micrographs of a integrated single-particle microelectrode[112]; (c) Photograph of the reaction chamber with a integrated single-particle microelectrode[113]"

Fig. 15

Charging and discharging curves of (a) a Si particle obtained using a contact-based single-particle microelectrode and (b) a tweezers-type of micro current collector[28]"

Fig. 16

(a) The fabricating process of pit-style single-particle microelectrodes[116]; (b) Schematic of the specially designed cell[116]; (c) SEM image of the pit-style single-particle microelectrode[116]; (d) Schematic of the ion-blocking electrode and its equivalent circuit model[116]; (e) Relationship between resistance, capacitance, and particle size fitted based on the equivalent circuit model[116]"

Fig. 17

(a) Schematic of the working principle of nano-impact method[124]; (b) Current-time curve during particle collision[119]; (c) Average collision current at different applying potentials[119]; (d) Oxidation current signals of NCM811 particles with different sizes[122]"

Table 1

Comparison of the above techniques for single particle measurments"

Fig. 18

CV curves of LiCo0.8Mn0.2O2 single-particle electrode (a) and composite electrode (b) [85]; (c) CV curves of TiNb2O7 single particles at different scan rates[109]; (d) Cyclic CV curves of LMO single particles[126]"

Fig. 19

Rate capability of (a) LCO single particles and (b) MCMB single particles[22, 90]"

Fig. 20

Nyquist plots and equivalent circuit models of LCO single particle[97] and MCMB single particle[89]"

Fig. 21

(a) Capacity retention of LCO single particles during 100 cycles based on the contact-based single particle microelectrode[28]; (b) Capacity retention of LTO single particles during 5000 cycles based on the integrated single particle microelectrode[108]"

Table 2

Electrochemical methods for obtaining kinetic parameters of single-particles"

Fig. 22

Volume expansion during delithiation process of a SiO x single particle[110]"

Fig. 23

(a) Schematic of a spectroelectrochemical cell for in situ Raman scattering spectroscopy of single particle microelectrodes[144]; Evolution of phase fractions during charge and discharge of single LMO polycrystalline particles (b)[144], single graphite flakes (c)[145], and single LMO crystalline particles (d)[146]"