With the development of electronics and ever-increasing demand for sustainable and versatile energy harvesting, thermoelectrics have become the subject of rapidly growing interest because they can directly transform thermal energy into valuable electrical power. The efficiency of thermoelectric materials is quantified by the dimensionless figure of merit ZT, defined as ZT = S 2 σT/κ, where S is the Seebeck coefficient, σ represents the electrical conductivity, and T denotes the absolute temperature. The thermal conductivity κ includes both lattice thermal conductivity κl and the electronic thermal conductivity κe. An ideal thermoelectric material should simultaneously exhibit high electrical conductivity to minimize internal energy loss, a high Seebeck coefficient for generating high voltage, and low thermal conductivity to maintain the temperature gradient. Motivated by these design principles, considerable efforts in the past decade have been devoted to exploring potential candidates that inherently possess the crucial attributes required for thermoelectric applications. Among the rapidly growing class of thermoelectric materials, layered compounds have shown advantages due to their unique crystal structure characterized by strong intralayer and weak interlayer bonds. Firstly, their strong discrepancy in chemical bonding strength is believed to induce partially-localized low-frequency phonon modes, low phonon group velocities, and large anharmonicity -all favourable for achieving low lattice thermal conductivity. Moreover, the low-dimensional structure translates to reduced dimensionality in the electrical transport properties, which can benefit thermoelectric performance. Furthermore, the anisotropic behaviour of electron and phonon transport in these layered systems provides an excellent opportunity to disentangle the interconnected thermoelectric parameters, especially when thermoelectric conversion occurs along the desired crystal direction within a single crystal. Within the layered compounds, the A2B2Q6 family (A = In, Cr, Bi, Sb or Sc; B = Si, Ge, and Q = Se, Te) has been intensively explored and some compounds show intriguing magnetic and magnetoelectric properties, such as pressure-driven spin-crossover and long-range ferromagnetic order. Interestingly, compounds based on A = Cr, Sb, In, and Bi are also reported to be promising candidates for thermoelectric applications. In particular, Sb2Si2Te6 has been the focus of interest due to its remarkable thermoelectric properties. Sb2Si2Te6 adopts a layered two-dimensional structure composed of Sb 3+ cations and [Si2Te6] 6-units, resembling the Fe2P2Se6 structure type. Owing to a low phonon group velocity and strong anharmonicity, Sb2Si2Te6 exhibits a relatively low thermal conductivity, approximately 1.3 W m -1 K -1 at room temperature, decreasing to 0.5 W m -1 K -1 at 823 K. Consequently, Sb2Si2Te6 achieves an impressive ZT of 1.08 at 823 K. Additionally, by constructing a cellular nanostructure through the deposition of a thin layer of Si2Te3 onto Sb2Si2Te6 grains, the peak ZT at 823 K can be improved to 1.65 in the Sb2Si2Te6/Si2Te3 cellular network. Nevertheless, the average power factor (PF) of Sb2Si2Te6 -approximately 10 μW cm - 1 K -2 within the temperature range of 400-823 K -lags behind that of conventional Pb-based thermoelectric materials (~30 μW cm -1 K -2 for p-type PbTe and ~20 μW cm - 1 K -2 for n-type PbTe). As a result, it is highly desirable to enhance the PF and, by extension, the overall thermoelectric performance of Sb2Si2Te6-based thermoelectric devices.